greenplumn xact 源码
greenplumn xact 代码
文件路径：/src/backend/access/transam/xact.c
/*-------------------------------------------------------------------------
*
* xact.c
* top level transaction system support routines
*
* See src/backend/access/transam/README for more information.
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/access/transam/xact.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <time.h>
#include <unistd.h>
#include "access/commit_ts.h"
#include "access/multixact.h"
#include "access/parallel.h"
#include "access/subtrans.h"
#include "access/transam.h"
#include "access/twophase.h"
#include "access/xact.h"
#include "access/xlog.h"
#include "access/xloginsert.h"
#include "access/xact_storage_tablespace.h"
#include "access/xlogutils.h"
#include "catalog/namespace.h"
#include "catalog/pg_enum.h"
#include "catalog/storage.h"
#include "catalog/storage_tablespace.h"
#include "catalog/storage_database.h"
#include "commands/async.h"
#include "commands/dbcommands.h"
#include "commands/extension.h"
#include "commands/resgroupcmds.h"
#include "commands/tablecmds.h"
#include "commands/trigger.h"
#include "executor/spi.h"
#include "libpq/be-fsstubs.h"
#include "libpq/pqsignal.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "replication/logical.h"
#include "replication/logicallauncher.h"
#include "replication/origin.h"
#include "replication/syncrep.h"
#include "replication/walsender.h"
#include "storage/condition_variable.h"
#include "storage/fd.h"
#include "storage/freespace.h"
#include "storage/lmgr.h"
#include "storage/md.h"
#include "storage/predicate.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "storage/sinvaladt.h"
#include "storage/smgr.h"
#include "utils/builtins.h"
#include "utils/catcache.h"
#include "utils/combocid.h"
#include "utils/faultinjector.h"
#include "utils/guc.h"
#include "utils/inval.h"
#include "utils/memutils.h"
#include "utils/relmapper.h"
#include "utils/builtins.h"
#include "utils/resource_manager.h"
#include "utils/sharedsnapshot.h"
#include "utils/snapmgr.h"
#include "utils/timeout.h"
#include "utils/timestamp.h"
#include "pg_trace.h"
#include "access/distributedlog.h"
#include "catalog/oid_dispatch.h"
#include "cdb/cdbdistributedsnapshot.h"
#include "cdb/cdbendpoint.h"
#include "cdb/cdbgang.h"
#include "cdb/cdblocaldistribxact.h"
#include "cdb/cdbtm.h"
#include "cdb/cdbvars.h" /* Gp_role, Gp_is_writer, interconnect_setup_timeout */
#include "utils/workfile_mgr.h"
#include "utils/vmem_tracker.h"
#include "cdb/cdbdisp.h"
#include "postmaster/autovacuum.h"
/*
* User-tweakable parameters
*/
int DefaultXactIsoLevel = XACT_READ_COMMITTED;
int XactIsoLevel;
bool DefaultXactReadOnly = false;
bool XactReadOnly;
bool DefaultXactDeferrable = false;
bool XactDeferrable;
int synchronous_commit = SYNCHRONOUS_COMMIT_ON;
/*
* When running as a parallel worker, we place only a single
* TransactionStateData on the parallel worker's state stack, and the XID
* reflected there will be that of the *innermost* currently-active
* subtransaction in the backend that initiated parallelism. However,
* GetTopTransactionId() and TransactionIdIsCurrentTransactionId()
* need to return the same answers in the parallel worker as they would have
* in the user backend, so we need some additional bookkeeping.
*
* XactTopFullTransactionId stores the XID of our toplevel transaction, which
* will be the same as TopTransactionState.fullTransactionId in an ordinary
* backend; but in a parallel backend, which does not have the entire
* transaction state, it will instead be copied from the backend that started
* the parallel operation.
*
* nParallelCurrentXids will be 0 and ParallelCurrentXids NULL in an ordinary
* backend, but in a parallel backend, nParallelCurrentXids will contain the
* number of XIDs that need to be considered current, and ParallelCurrentXids
* will contain the XIDs themselves. This includes all XIDs that were current
* or sub-committed in the parent at the time the parallel operation began.
* The XIDs are stored sorted in numerical order (not logical order) to make
* lookups as fast as possible.
*/
FullTransactionId XactTopFullTransactionId = {InvalidTransactionId};
int nParallelCurrentXids = 0;
TransactionId *ParallelCurrentXids;
int32 gp_subtrans_warn_limit = 16777216; /* 16 million */
/* gp-specific
* routine for marking when a sequence makes a mark in the xlog. we need
* to keep track of this because sequences are the only reason a reader should
* ever write to the xlog during commit. As a result, we keep track of such
* and will complain loudly if its violated.
*/
bool seqXlogWrite;
/*
* Miscellaneous flag bits to record events which occur on the top level
* transaction. These flags are only persisted in MyXactFlags and are intended
* so we remember to do certain things later on in the transaction. This is
* globally accessible, so can be set from anywhere in the code that requires
* recording flags.
*
* Flag XACT_FLAGS_ACCESSEDTEMPREL not used in GPDB, see comments in
* PrepareTransaction()
*/
int MyXactFlags;
/*
* transaction states - transaction state from server perspective
*/
typedef enum TransState
{
TRANS_DEFAULT, /* idle */
TRANS_START, /* transaction starting */
TRANS_INPROGRESS, /* inside a valid transaction */
TRANS_COMMIT, /* commit in progress */
TRANS_ABORT, /* abort in progress */
TRANS_PREPARE /* prepare in progress */
} TransState;
/*
* transaction block states - transaction state of client queries
*
* Note: the subtransaction states are used only for non-topmost
* transactions; the others appear only in the topmost transaction.
*/
typedef enum TBlockState
{
/* not-in-transaction-block states */
TBLOCK_DEFAULT, /* idle */
TBLOCK_STARTED, /* running single-query transaction */
/* transaction block states */
TBLOCK_BEGIN, /* starting transaction block */
TBLOCK_INPROGRESS, /* live transaction */
TBLOCK_IMPLICIT_INPROGRESS, /* live transaction after implicit BEGIN */
TBLOCK_PARALLEL_INPROGRESS, /* live transaction inside parallel worker */
TBLOCK_END, /* COMMIT received */
TBLOCK_ABORT, /* failed xact, awaiting ROLLBACK */
TBLOCK_ABORT_END, /* failed xact, ROLLBACK received */
TBLOCK_ABORT_PENDING, /* live xact, ROLLBACK received */
TBLOCK_PREPARE, /* live xact, PREPARE received */
/* subtransaction states */
TBLOCK_SUBBEGIN, /* starting a subtransaction */
TBLOCK_SUBINPROGRESS, /* live subtransaction */
TBLOCK_SUBRELEASE, /* RELEASE received */
TBLOCK_SUBCOMMIT, /* COMMIT received while TBLOCK_SUBINPROGRESS */
TBLOCK_SUBABORT, /* failed subxact, awaiting ROLLBACK */
TBLOCK_SUBABORT_END, /* failed subxact, ROLLBACK received */
TBLOCK_SUBABORT_PENDING, /* live subxact, ROLLBACK received */
TBLOCK_SUBRESTART, /* live subxact, ROLLBACK TO received */
TBLOCK_SUBABORT_RESTART /* failed subxact, ROLLBACK TO received */
} TBlockState;
/*
* transaction state structure
*/
typedef struct TransactionStateData
{
FullTransactionId fullTransactionId; /* my FullTransactionId */
SubTransactionId subTransactionId; /* my subxact ID */
char *name; /* savepoint name, if any */
int savepointLevel; /* savepoint level */
TransState state; /* low-level state */
TBlockState blockState; /* high-level state */
int nestingLevel; /* transaction nesting depth */
int gucNestLevel; /* GUC context nesting depth */
MemoryContext curTransactionContext; /* my xact-lifetime context */
ResourceOwner curTransactionOwner; /* my query resources */
TransactionId *childXids; /* subcommitted child XIDs, in XID order */
int nChildXids; /* # of subcommitted child XIDs */
int maxChildXids; /* allocated size of childXids[] */
Oid prevUser; /* previous CurrentUserId setting */
int prevSecContext; /* previous SecurityRestrictionContext */
bool prevXactReadOnly; /* entry-time xact r/o state */
bool startedInRecovery; /* did we start in recovery? */
bool didLogXid; /* has xid been included in WAL record? */
int parallelModeLevel; /* Enter/ExitParallelMode counter */
bool chain; /* start a new block after this one */
bool executorSaysXactDoesWrites; /* GP executor says xact does writes */
struct TransactionStateData *parent; /* back link to parent */
struct TransactionStateData *fastLink; /* back link to jump to parent for efficient search */
} TransactionStateData;
static bool TopXactexecutorDidWriteXLog; /* QE has wrote xlog */
typedef TransactionStateData *TransactionState;
#define NUM_NODES_TO_SKIP_FOR_FAST_SEARCH 100
static int fastNodeCount;
static TransactionState previousFastLink;
/*
* Serialized representation used to transmit transaction state to parallel
* workers through shared memory.
*/
typedef struct SerializedTransactionState
{
int xactIsoLevel;
bool xactDeferrable;
FullTransactionId topFullTransactionId;
FullTransactionId currentFullTransactionId;
CommandId currentCommandId;
int nParallelCurrentXids;
TransactionId parallelCurrentXids[FLEXIBLE_ARRAY_MEMBER];
} SerializedTransactionState;
/* The size of SerializedTransactionState, not including the final array. */
#define SerializedTransactionStateHeaderSize \
offsetof(SerializedTransactionState, parallelCurrentXids)
/*
* CurrentTransactionState always points to the current transaction state
* block. It will point to TopTransactionStateData when not in a
* transaction at all, or when in a top-level transaction.
*/
static TransactionStateData TopTransactionStateData = {
.state = TRANS_DEFAULT,
.blockState = TBLOCK_DEFAULT,
};
/*
* unreportedXids holds XIDs of all subtransactions that have not yet been
* reported in an XLOG_XACT_ASSIGNMENT record.
*/
static int nUnreportedXids;
static TransactionId unreportedXids[PGPROC_MAX_CACHED_SUBXIDS];
static TransactionState CurrentTransactionState = &TopTransactionStateData;
/*
* The subtransaction ID and command ID assignment counters are global
* to a whole transaction, so we do not keep them in the state stack.
*/
static SubTransactionId currentSubTransactionId;
static CommandId currentCommandId;
static bool currentCommandIdUsed;
/*
* xactStartTimestamp is the value of transaction_timestamp().
* stmtStartTimestamp is the value of statement_timestamp().
* xactStopTimestamp is the time at which we log a commit or abort WAL record.
* These do not change as we enter and exit subtransactions, so we don't
* keep them inside the TransactionState stack.
*/
static TimestampTz xactStartTimestamp;
static TimestampTz stmtStartTimestamp;
static TimestampTz xactStopTimestamp;
/*
* Total number of SAVEPOINT commands executed by this transaction.
*
*/
static int currentSavepointTotal;
/*
* GID to be used for preparing the current transaction. This is also
* global to a whole transaction, so we don't keep it in the state stack.
*/
static char *prepareGID;
/*
* Some commands want to force synchronous commit.
*/
static bool forceSyncCommit = false;
/* Flag for logging statements in a transaction. */
bool xact_is_sampled = false;
/*
* Private context for transaction-abort work --- we reserve space for this
* at startup to ensure that AbortTransaction and AbortSubTransaction can work
* when we've run out of memory.
*/
static MemoryContext TransactionAbortContext = NULL;
/*
* List of add-on start- and end-of-xact callbacks
*/
typedef struct XactCallbackItem
{
struct XactCallbackItem *next;
XactCallback callback;
void *arg;
} XactCallbackItem;
static XactCallbackItem *Xact_callbacks = NULL;
static XactCallbackItem *Xact_callbacks_once = NULL;
/*
* List of add-on start- and end-of-subxact callbacks
*/
typedef struct SubXactCallbackItem
{
struct SubXactCallbackItem *next;
SubXactCallback callback;
void *arg;
} SubXactCallbackItem;
static SubXactCallbackItem *SubXact_callbacks = NULL;
/*
* Subtransaction file used to keep subtransaction Ids that spill over from
* shared snapshot. Kept outside of shared snapshot because readers and writer
* have their own File pointer.
*/
File subxip_file = 0;
/* local function prototypes */
static void AssignTransactionId(TransactionState s);
static void AbortTransaction(void);
static void AtAbort_Memory(void);
static void AtCleanup_Memory(void);
static void AtAbort_ResourceOwner(void);
static void AtCCI_LocalCache(void);
static void AtCommit_Memory(void);
static void AtStart_Cache(void);
static void AtStart_Memory(void);
static void AtStart_ResourceOwner(void);
static void CallXactCallbacks(XactEvent event);
static void CallXactCallbacksOnce(XactEvent event);
static void CallSubXactCallbacks(SubXactEvent event,
SubTransactionId mySubid,
SubTransactionId parentSubid);
static void CleanupTransaction(void);
static void CheckTransactionBlock(bool isTopLevel, bool throwError,
const char *stmtType);
static void CommitTransaction(void);
static TransactionId RecordTransactionAbort(bool isSubXact);
static void StartTransaction(void);
static void StartSubTransaction(void);
static void CommitSubTransaction(void);
static void AbortSubTransaction(void);
static void CleanupSubTransaction(void);
static void PushTransaction(void);
static void PopTransaction(void);
static void AtSubAbort_Memory(void);
static void AtSubCleanup_Memory(void);
static void AtSubAbort_ResourceOwner(void);
static void AtSubCommit_Memory(void);
static void AtSubStart_Memory(void);
static void AtSubStart_ResourceOwner(void);
static void EndLocalDistribXact(bool isCommit);
static void ShowTransactionState(const char *str);
static void ShowTransactionStateRec(const char *str, TransactionState state);
static const char *BlockStateAsString(TBlockState blockState);
static const char *TransStateAsString(TransState state);
static void DispatchRollbackToSavepoint(char *name);
static bool IsCurrentTransactionIdForReader(TransactionId xid);
/* ----------------------------------------------------------------
* transaction state accessors
* ----------------------------------------------------------------
*/
/*
* IsTransactionState
*
* This returns true if we are inside a valid transaction; that is,
* it is safe to initiate database access, take heavyweight locks, etc.
*/
bool
IsTransactionState(void)
{
TransactionState s = CurrentTransactionState;
/*
* TRANS_DEFAULT and TRANS_ABORT are obviously unsafe states. However, we
* also reject the startup/shutdown states TRANS_START, TRANS_COMMIT,
* TRANS_PREPARE since it might be too soon or too late within those
* transition states to do anything interesting. Hence, the only "valid"
* state is TRANS_INPROGRESS.
*/
return (s->state == TRANS_INPROGRESS);
}
bool
IsAbortInProgress(void)
{
TransactionState s = CurrentTransactionState;
return (s->state == TRANS_ABORT);
}
bool
IsTransactionPreparing(void)
{
TransactionState s = CurrentTransactionState;
return (s->state == TRANS_PREPARE);
}
/*
* IsAbortedTransactionBlockState
*
* This returns true if we are within an aborted transaction block.
*/
bool
IsAbortedTransactionBlockState(void)
{
TransactionState s = CurrentTransactionState;
if (s->blockState == TBLOCK_ABORT ||
s->blockState == TBLOCK_SUBABORT)
return true;
return false;
}
bool
TransactionDidWriteXLog(void)
{
TransactionState s = CurrentTransactionState;
return s->didLogXid;
}
bool
TopXactExecutorDidWriteXLog(void)
{
return TopXactexecutorDidWriteXLog;
}
void
GetAllTransactionXids(
DistributedTransactionId *distribXid,
TransactionId *localXid,
TransactionId *subXid)
{
TransactionState s = CurrentTransactionState;
*distribXid = getDistributedTransactionId();
*localXid = XidFromFullTransactionId(s->fullTransactionId);
*subXid = s->subTransactionId;
}
/*
* GetTopTransactionId
*
* This will return the XID of the main transaction, assigning one if
* it's not yet set. Be careful to call this only inside a valid xact.
*/
TransactionId
GetTopTransactionId(void)
{
if (!FullTransactionIdIsValid(XactTopFullTransactionId))
AssignTransactionId(&TopTransactionStateData);
return XidFromFullTransactionId(XactTopFullTransactionId);
}
/*
* GetTopTransactionIdIfAny
*
* This will return the XID of the main transaction, if one is assigned.
* It will return InvalidTransactionId if we are not currently inside a
* transaction, or inside a transaction that hasn't yet been assigned an XID.
*/
TransactionId
GetTopTransactionIdIfAny(void)
{
return XidFromFullTransactionId(XactTopFullTransactionId);
}
/*
* GetCurrentTransactionId
*
* This will return the XID of the current transaction (main or sub
* transaction), assigning one if it's not yet set. Be careful to call this
* only inside a valid xact.
*/
TransactionId
GetCurrentTransactionId(void)
{
TransactionState s = CurrentTransactionState;
if (!FullTransactionIdIsValid(s->fullTransactionId))
AssignTransactionId(s);
return XidFromFullTransactionId(s->fullTransactionId);
}
/*
* GetCurrentTransactionIdIfAny
*
* This will return the XID of the current sub xact, if one is assigned.
* It will return InvalidTransactionId if we are not currently inside a
* transaction, or inside a transaction that hasn't been assigned an XID yet.
*/
TransactionId
GetCurrentTransactionIdIfAny(void)
{
return XidFromFullTransactionId(CurrentTransactionState->fullTransactionId);
}
/*
* GetTopFullTransactionId
*
* This will return the FullTransactionId of the main transaction, assigning
* one if it's not yet set. Be careful to call this only inside a valid xact.
*/
FullTransactionId
GetTopFullTransactionId(void)
{
if (!FullTransactionIdIsValid(XactTopFullTransactionId))
AssignTransactionId(&TopTransactionStateData);
return XactTopFullTransactionId;
}
/*
* GetTopFullTransactionIdIfAny
*
* This will return the FullTransactionId of the main transaction, if one is
* assigned. It will return InvalidFullTransactionId if we are not currently
* inside a transaction, or inside a transaction that hasn't yet been assigned
* one.
*/
FullTransactionId
GetTopFullTransactionIdIfAny(void)
{
return XactTopFullTransactionId;
}
/*
* GetCurrentFullTransactionId
*
* This will return the FullTransactionId of the current transaction (main or
* sub transaction), assigning one if it's not yet set. Be careful to call
* this only inside a valid xact.
*/
FullTransactionId
GetCurrentFullTransactionId(void)
{
TransactionState s = CurrentTransactionState;
if (!FullTransactionIdIsValid(s->fullTransactionId))
AssignTransactionId(s);
return s->fullTransactionId;
}
/*
* GetCurrentFullTransactionIdIfAny
*
* This will return the FullTransactionId of the current sub xact, if one is
* assigned. It will return InvalidFullTransactionId if we are not currently
* inside a transaction, or inside a transaction that hasn't been assigned one
* yet.
*/
FullTransactionId
GetCurrentFullTransactionIdIfAny(void)
{
return CurrentTransactionState->fullTransactionId;
}
/*
* MarkCurrentTransactionIdLoggedIfAny
*
* Remember that the current xid - if it is assigned - now has been wal logged.
*/
void
MarkCurrentTransactionIdLoggedIfAny(void)
{
if (FullTransactionIdIsValid(CurrentTransactionState->fullTransactionId))
CurrentTransactionState->didLogXid = true;
}
void
MarkTopTransactionWriteXLogOnExecutor(void)
{
TopXactexecutorDidWriteXLog = true;
}
/*
* GetStableLatestTransactionId
*
* Get the transaction's XID if it has one, else read the next-to-be-assigned
* XID. Once we have a value, return that same value for the remainder of the
* current transaction. This is meant to provide the reference point for the
* age(xid) function, but might be useful for other maintenance tasks as well.
*/
TransactionId
GetStableLatestTransactionId(void)
{
static LocalTransactionId lxid = InvalidLocalTransactionId;
static TransactionId stablexid = InvalidTransactionId;
if (lxid != MyProc->lxid)
{
lxid = MyProc->lxid;
stablexid = GetTopTransactionIdIfAny();
if (!TransactionIdIsValid(stablexid))
stablexid = ReadNewTransactionId();
}
Assert(TransactionIdIsValid(stablexid));
return stablexid;
}
/*
* AssignTransactionId
*
* Assigns a new permanent FullTransactionId to the given TransactionState.
* We do not assign XIDs to transactions until/unless this is called.
* Also, any parent TransactionStates that don't yet have XIDs are assigned
* one; this maintains the invariant that a child transaction has an XID
* following its parent's.
*/
static void
AssignTransactionId(TransactionState s)
{
bool isSubXact = (s->parent != NULL);
ResourceOwner currentOwner;
bool log_unknown_top = false;
/* Assert that caller didn't screw up */
Assert(!FullTransactionIdIsValid(s->fullTransactionId));
Assert(s->state == TRANS_INPROGRESS);
if (DistributedTransactionContext == DTX_CONTEXT_QE_READER ||
DistributedTransactionContext == DTX_CONTEXT_QE_ENTRY_DB_SINGLETON)
{
elog(ERROR, "AssignTransactionId() called by %s process",
DtxContextToString(DistributedTransactionContext));
}
/*
* Workers synchronize transaction state at the beginning of each parallel
* operation, so we can't account for new XIDs at this point.
*/
if (IsInParallelMode() || IsParallelWorker())
elog(ERROR, "cannot assign XIDs during a parallel operation");
/*
* Ensure parent(s) have XIDs, so that a child always has an XID later
* than its parent. Mustn't recurse here, or we might get a stack
* overflow if we're at the bottom of a huge stack of subtransactions none
* of which have XIDs yet.
*/
if (isSubXact && !FullTransactionIdIsValid(s->parent->fullTransactionId))
{
TransactionState p = s->parent;
TransactionState *parents;
size_t parentOffset = 0;
parents = palloc(sizeof(TransactionState) * s->nestingLevel);
while (p != NULL && !FullTransactionIdIsValid(p->fullTransactionId))
{
parents[parentOffset++] = p;
p = p->parent;
}
/*
* This is technically a recursive call, but the recursion will never
* be more than one layer deep.
*/
while (parentOffset != 0)
AssignTransactionId(parents[--parentOffset]);
pfree(parents);
}
/*
* When wal_level=logical, guarantee that a subtransaction's xid can only
* be seen in the WAL stream if its toplevel xid has been logged before.
* If necessary we log an xact_assignment record with fewer than
* PGPROC_MAX_CACHED_SUBXIDS. Note that it is fine if didLogXid isn't set
* for a transaction even though it appears in a WAL record, we just might
* superfluously log something. That can happen when an xid is included
* somewhere inside a wal record, but not in XLogRecord->xl_xid, like in
* xl_standby_locks.
*/
if (isSubXact && XLogLogicalInfoActive() &&
!TopTransactionStateData.didLogXid)
log_unknown_top = true;
/*
* Generate a new FullTransactionId and record its xid in PG_PROC and
* pg_subtrans.
*
* NB: we must make the subtrans entry BEFORE the Xid appears anywhere in
* shared storage other than PG_PROC; because if there's no room for it in
* PG_PROC, the subtrans entry is needed to ensure that other backends see
* the Xid as "running". See GetNewTransactionId.
*/
s->fullTransactionId = GetNewTransactionId(isSubXact);
ereportif(Debug_print_full_dtm, LOG,
(errmsg("AssignTransactionId(): assigned xid " UINT64_FORMAT,
U64FromFullTransactionId(s->fullTransactionId))));
if (!isSubXact)
XactTopFullTransactionId = s->fullTransactionId;
if (isSubXact)
{
Assert(TransactionIdPrecedes(U64FromFullTransactionId(s->parent->fullTransactionId),
U64FromFullTransactionId(s->fullTransactionId)));
SubTransSetParent(XidFromFullTransactionId(s->fullTransactionId),
XidFromFullTransactionId(s->parent->fullTransactionId));
}
/*
* If it's a top-level transaction, the predicate locking system needs to
* be told about it too.
*/
if (!isSubXact)
RegisterPredicateLockingXid(XidFromFullTransactionId(s->fullTransactionId));
/*
* Acquire lock on the transaction XID. (We assume this cannot block.) We
* have to ensure that the lock is assigned to the transaction's own
* ResourceOwner.
*/
currentOwner = CurrentResourceOwner;
CurrentResourceOwner = s->curTransactionOwner;
XactLockTableInsert(XidFromFullTransactionId(s->fullTransactionId));
CurrentResourceOwner = currentOwner;
/*
* Every PGPROC_MAX_CACHED_SUBXIDS assigned transaction ids within each
* top-level transaction we issue a WAL record for the assignment. We
* include the top-level xid and all the subxids that have not yet been
* reported using XLOG_XACT_ASSIGNMENT records.
*
* This is required to limit the amount of shared memory required in a hot
* standby server to keep track of in-progress XIDs. See notes for
* RecordKnownAssignedTransactionIds().
*
* We don't keep track of the immediate parent of each subxid, only the
* top-level transaction that each subxact belongs to. This is correct in
* recovery only because aborted subtransactions are separately WAL
* logged.
*
* This is correct even for the case where several levels above us didn't
* have an xid assigned as we recursed up to them beforehand.
*/
if (isSubXact && XLogStandbyInfoActive())
{
unreportedXids[nUnreportedXids] = XidFromFullTransactionId(s->fullTransactionId);
nUnreportedXids++;
/*
* ensure this test matches similar one in
* RecoverPreparedTransactions()
*/
if (nUnreportedXids >= PGPROC_MAX_CACHED_SUBXIDS ||
log_unknown_top)
{
xl_xact_assignment xlrec;
/*
* xtop is always set by now because we recurse up transaction
* stack to the highest unassigned xid and then come back down
*/
xlrec.xtop = GetTopTransactionId();
Assert(TransactionIdIsValid(xlrec.xtop));
xlrec.nsubxacts = nUnreportedXids;
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, MinSizeOfXactAssignment);
XLogRegisterData((char *) unreportedXids,
nUnreportedXids * sizeof(TransactionId));
(void) XLogInsert(RM_XACT_ID, XLOG_XACT_ASSIGNMENT);
nUnreportedXids = 0;
/* mark top, not current xact as having been logged */
TopTransactionStateData.didLogXid = true;
}
}
}
/*
* GetCurrentSubTransactionId
*/
SubTransactionId
GetCurrentSubTransactionId(void)
{
TransactionState s = CurrentTransactionState;
return s->subTransactionId;
}
/*
* SubTransactionIsActive
*
* Test if the specified subxact ID is still active. Note caller is
* responsible for checking whether this ID is relevant to the current xact.
*/
bool
SubTransactionIsActive(SubTransactionId subxid)
{
TransactionState s;
for (s = CurrentTransactionState; s != NULL; s = s->parent)
{
if (s->state == TRANS_ABORT)
continue;
if (s->subTransactionId == subxid)
return true;
}
return false;
}
/*
* GetCurrentCommandId
*
* "used" must be true if the caller intends to use the command ID to mark
* inserted/updated/deleted tuples. false means the ID is being fetched
* for read-only purposes (ie, as a snapshot validity cutoff). See
* CommandCounterIncrement() for discussion.
*/
CommandId
GetCurrentCommandId(bool used)
{
/* this is global to a transaction, not subtransaction-local */
if (used)
{
/*
* Forbid setting currentCommandIdUsed in a parallel worker, because
* we have no provision for communicating this back to the master. We
* could relax this restriction when currentCommandIdUsed was already
* true at the start of the parallel operation.
*/
Assert(!IsParallelWorker());
currentCommandIdUsed = true;
}
return currentCommandId;
}
/*
* SetParallelStartTimestamps
*
* In a parallel worker, we should inherit the parent transaction's
* timestamps rather than setting our own. The parallel worker
* infrastructure must call this to provide those values before
* calling StartTransaction() or SetCurrentStatementStartTimestamp().
*/
void
SetParallelStartTimestamps(TimestampTz xact_ts, TimestampTz stmt_ts)
{
Assert(IsParallelWorker());
xactStartTimestamp = xact_ts;
stmtStartTimestamp = stmt_ts;
}
/*
* GetCurrentTransactionStartTimestamp
*/
TimestampTz
GetCurrentTransactionStartTimestamp(void)
{
return xactStartTimestamp;
}
/*
* GetCurrentStatementStartTimestamp
*/
TimestampTz
GetCurrentStatementStartTimestamp(void)
{
return stmtStartTimestamp;
}
/*
* GetCurrentTransactionStopTimestamp
*
* We return current time if the transaction stop time hasn't been set
* (which can happen if we decide we don't need to log an XLOG record).
*/
TimestampTz
GetCurrentTransactionStopTimestamp(void)
{
if (xactStopTimestamp != 0)
return xactStopTimestamp;
return GetCurrentTimestamp();
}
/*
* SetCurrentStatementStartTimestamp
*
* In a parallel worker, this should already have been provided by a call
* to SetParallelStartTimestamps().
*/
void
SetCurrentStatementStartTimestamp(void)
{
if (!IsParallelWorker())
stmtStartTimestamp = GetCurrentTimestamp();
else
Assert(stmtStartTimestamp != 0);
}
/*
* SetCurrentTransactionStopTimestamp
*/
static inline void
SetCurrentTransactionStopTimestamp(void)
{
xactStopTimestamp = GetCurrentTimestamp();
}
/*
* GetCurrentTransactionNestLevel
*
* Note: this will return zero when not inside any transaction, one when
* inside a top-level transaction, etc.
*/
int
GetCurrentTransactionNestLevel(void)
{
TransactionState s = CurrentTransactionState;
return s->nestingLevel;
}
/*
* We will return true for the Xid of the current subtransaction, any of
* its subcommitted children, any of its parents, or any of their
* previously subcommitted children. However, a transaction being aborted
* is no longer "current", even though it may still have an entry on the
* state stack.
*
* The XID of a child is always greater than that of its parent.
* Taking advantage of this fact simple optimizations are added instead of linear traversal to fasten the search
* 1] Added fastLink/skipLink pointers to skip nodes in list and scan fast across, instead of visiting all nodes in list
* 2] Break-out as soon as XID to search is greater than the current node in (parent / child) list
*/
static bool
TransactionIdIsCurrentTransactionIdInternal(TransactionId xid)
{
TransactionState s = CurrentTransactionState;
while (s != NULL)
{
if (s->state != TRANS_ABORT &&
FullTransactionIdIsValid(s->fullTransactionId))
{
int low,
high;
if (TransactionIdEquals(xid, XidFromFullTransactionId(s->fullTransactionId)))
return true;
/* As the childXids array is ordered, we can use binary search */
low = 0;
high = s->nChildXids - 1;
while (low <= high)
{
int middle;
TransactionId probe;
middle = low + (high - low) / 2;
probe = s->childXids[middle];
if (TransactionIdEquals(probe, xid))
return true;
else if (TransactionIdPrecedes(probe, xid))
low = middle + 1;
else
high = middle - 1;
}
/*
* If not found in childXID list and greater than s->fullTransactionId
* it cannot be on stack below this node,
* as stack is in decreasing order of XIDs
* So, can safely breakout.
*/
if (TransactionIdFollows(xid, XidFromFullTransactionId(s->fullTransactionId)))
break;
}
if (s->fastLink)
{
if (TransactionIdPrecedesOrEquals(xid, XidFromFullTransactionId(s->fastLink->fullTransactionId)))
{
s = s->fastLink;
continue;
}
}
s = s->parent;
}
return false;
}
/*
* IsCurrentTransactionIdForReader
*
* We can either be a cursor reader or normal reader.
*
* The writer_proc will contain all of the subtransaction xids of the current transaction.
* - case 1: check writer's top transaction id
* - case 2: if not, check writer's subtransactions
* - case 3: if overflowed, check topmostxid from pg_subtrans with writer's top transaction id
*/
static
bool IsCurrentTransactionIdForReader(TransactionId xid)
{
Assert(!Gp_is_writer);
Assert(SharedLocalSnapshotSlot);
LWLockAcquire(SharedLocalSnapshotSlot->slotLock, LW_SHARED);
PGPROC* writer_proc = SharedLocalSnapshotSlot->writer_proc;
PGXACT* writer_xact = SharedLocalSnapshotSlot->writer_xact;
if (!writer_proc)
{
LWLockRelease(SharedLocalSnapshotSlot->slotLock);
elog(ERROR, "reference to writer proc not found in shared snapshot");
}
else if (!writer_proc->pid)
{
LWLockRelease(SharedLocalSnapshotSlot->slotLock);
elog(ERROR, "writer proc reference shared with reader is invalid");
}
TransactionId writer_xid = writer_xact->xid;
bool overflowed = writer_xact->overflowed;
bool isCurrent = false;
if (TransactionIdIsValid(writer_xid))
{
/*
* Case 1: check top transaction id
*/
if (TransactionIdEquals(xid, writer_xid))
{
ereportif(Debug_print_full_dtm, LOG,
(errmsg("reader encountered writer's top xid %u", xid)));
isCurrent = true;
}
else
{
/*
* Case 2: check cached subtransaction ids from latest to earliest
*/
int subx_index = writer_xact->nxids - 1;
while (!isCurrent && subx_index >= 0)
{
isCurrent = TransactionIdEquals(writer_proc->subxids.xids[subx_index], xid);
subx_index--;
}
}
}
/* release the lock before accessing pg_subtrans */
LWLockRelease(SharedLocalSnapshotSlot->slotLock);
/*
* Case 3: if subxids overflowed, check topmostxid of xid from pg_subtrans
*/
if (!isCurrent && overflowed)
{
Assert(TransactionIdIsValid(writer_xid));
/*
* QE readers don't have access to writer's transaction state.
* Therefore, unlike writer, readers have to lookup pg_subtrans, which
* is more expensive than searching for an xid in transaction state. If
* xid is older than the oldest running transaction we know of, it is
* definitely not current and we can skip pg_subtrans. Note that
* pg_subtrans is not guaranteed to exist for transactions that are
* known to be finished.
*/
if (TransactionIdFollowsOrEquals(xid, TransactionXmin) &&
TransactionIdEquals(SubTransGetTopmostTransaction(xid), writer_xid))
{
/*
* xid is a subtransaction of current transaction. Did it abort?
* If this was a writer, TransactionIdIsCurrentTransactionId()
* returns false for aborted subtransactions. We must therefore
* consult clog. In a writer, this information is available in
* CurrentTransactionState.
*/
isCurrent = TransactionIdDidAbortForReader(xid) ? false : true;
}
}
ereportif(isCurrent && Debug_print_full_dtm, LOG,
(errmsg("reader encountered writer's subxact ID %u", xid)));
return isCurrent;
}
/*
* TransactionIdIsCurrentTransactionId
*/
bool
TransactionIdIsCurrentTransactionId(TransactionId xid)
{
bool isCurrentTransactionId = false;
/*
* We always say that BootstrapTransactionId is "not my transaction ID"
* even when it is (ie, during bootstrap). Along with the fact that
* transam.c always treats BootstrapTransactionId as already committed,
* this causes the heapam_visibility.c routines to see all tuples as
* committed, which is what we need during bootstrap. (Bootstrap mode
* only inserts tuples, it never updates or deletes them, so all tuples
* can be presumed good immediately.)
*
* Likewise, InvalidTransactionId and FrozenTransactionId are certainly
* not my transaction ID, so we can just return "false" immediately for
* any non-normal XID.
*/
if (!TransactionIdIsNormal(xid))
return false;
/*
* In parallel workers, the XIDs we must consider as current are stored in
* ParallelCurrentXids rather than the transaction-state stack. Note that
* the XIDs in this array are sorted numerically rather than according to
* transactionIdPrecedes order.
*/
if (nParallelCurrentXids > 0)
{
int low,
high;
low = 0;
high = nParallelCurrentXids - 1;
while (low <= high)
{
int middle;
TransactionId probe;
middle = low + (high - low) / 2;
probe = ParallelCurrentXids[middle];
if (probe == xid)
return true;
else if (probe < xid)
low = middle + 1;
else
high = middle - 1;
}
return false;
}
if (DistributedTransactionContext == DTX_CONTEXT_QE_READER ||
DistributedTransactionContext == DTX_CONTEXT_QE_ENTRY_DB_SINGLETON)
{
isCurrentTransactionId = IsCurrentTransactionIdForReader(xid);
ereportif(Debug_print_full_dtm, LOG,
(errmsg("qExec Reader xid = %u, is current = %s",
xid, (isCurrentTransactionId ? "true" : "false"))));
return isCurrentTransactionId;
}
/* we aren't a reader */
Assert(DistributedTransactionContext != DTX_CONTEXT_QE_ENTRY_DB_SINGLETON);
return TransactionIdIsCurrentTransactionIdInternal(xid);
}
/*
* TransactionStartedDuringRecovery
*
* Returns true if the current transaction started while recovery was still
* in progress. Recovery might have ended since so RecoveryInProgress() might
* return false already.
*/
bool
TransactionStartedDuringRecovery(void)
{
return CurrentTransactionState->startedInRecovery;
}
/*
* EnterParallelMode
*/
void
EnterParallelMode(void)
{
TransactionState s = CurrentTransactionState;
Assert(s->parallelModeLevel >= 0);
++s->parallelModeLevel;
}
/*
* ExitParallelMode
*/
void
ExitParallelMode(void)
{
TransactionState s = CurrentTransactionState;
Assert(s->parallelModeLevel > 0);
Assert(s->parallelModeLevel > 1 || !ParallelContextActive());
--s->parallelModeLevel;
}
/*
* IsInParallelMode
*
* Are we in a parallel operation, as either the master or a worker? Check
* this to prohibit operations that change backend-local state expected to
* match across all workers. Mere caches usually don't require such a
* restriction. State modified in a strict push/pop fashion, such as the
* active snapshot stack, is often fine.
*/
bool
IsInParallelMode(void)
{
return CurrentTransactionState->parallelModeLevel != 0;
}
/*
* CommandCounterIncrement
*/
void
CommandCounterIncrement(void)
{
/*
* If the current value of the command counter hasn't been "used" to mark
* tuples, we need not increment it, since there's no need to distinguish
* a read-only command from others. This helps postpone command counter
* overflow, and keeps no-op CommandCounterIncrement operations cheap.
*/
if (currentCommandIdUsed)
{
/*
* Workers synchronize transaction state at the beginning of each
* parallel operation, so we can't account for new commands after that
* point.
*/
if (IsInParallelMode() || IsParallelWorker())
elog(ERROR, "cannot start commands during a parallel operation");
currentCommandId += 1;
if (currentCommandId == InvalidCommandId)
{
currentCommandId -= 1;
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("cannot have more than 2^32-2 commands in a transaction")));
}
currentCommandIdUsed = false;
/* Propagate new command ID into static snapshots */
SnapshotSetCommandId(currentCommandId);
/*
* Make any catalog changes done by the just-completed command visible
* in the local syscache. We obviously don't need to do this after a
* read-only command. (But see hacks in inval.c to make real sure we
* don't think a command that queued inval messages was read-only.)
*/
AtCCI_LocalCache();
}
}
/*
* ForceSyncCommit
*
* Interface routine to allow commands to force a synchronous commit of the
* current top-level transaction
*/
void
ForceSyncCommit(void)
{
forceSyncCommit = true;
}
/* ----------------------------------------------------------------
* StartTransaction stuff
* ----------------------------------------------------------------
*/
/*
* AtStart_Cache
*/
static void
AtStart_Cache(void)
{
AcceptInvalidationMessages();
}
/*
* AtStart_Memory
*/
static void
AtStart_Memory(void)
{
TransactionState s = CurrentTransactionState;
/*
* If this is the first time through, create a private context for
* AbortTransaction to work in. By reserving some space now, we can
* insulate AbortTransaction from out-of-memory scenarios. Like
* ErrorContext, we set it up with slow growth rate and a nonzero minimum
* size, so that space will be reserved immediately.
*/
if (TransactionAbortContext == NULL)
TransactionAbortContext =
AllocSetContextCreate(TopMemoryContext,
"TransactionAbortContext",
32 * 1024,
32 * 1024,
32 * 1024);
/*
* We shouldn't have a transaction context already.
*/
Assert(TopTransactionContext == NULL);
/*
* Create a toplevel context for the transaction.
*/
TopTransactionContext =
AllocSetContextCreate(TopMemoryContext,
"TopTransactionContext",
ALLOCSET_DEFAULT_SIZES);
/*
* In a top-level transaction, CurTransactionContext is the same as
* TopTransactionContext.
*/
CurTransactionContext = TopTransactionContext;
s->curTransactionContext = CurTransactionContext;
/* Make the CurTransactionContext active. */
MemoryContextSwitchTo(CurTransactionContext);
}
/*
* AtStart_ResourceOwner
*/
static void
AtStart_ResourceOwner(void)
{
TransactionState s = CurrentTransactionState;
/*
* We shouldn't have a transaction resource owner already.
*/
Assert(TopTransactionResourceOwner == NULL);
/*
* Create a toplevel resource owner for the transaction.
*/
s->curTransactionOwner = ResourceOwnerCreate(NULL, "TopTransaction");
TopTransactionResourceOwner = s->curTransactionOwner;
CurTransactionResourceOwner = s->curTransactionOwner;
CurrentResourceOwner = s->curTransactionOwner;
}
/* ----------------------------------------------------------------
* StartSubTransaction stuff
* ----------------------------------------------------------------
*/
/*
* AtSubStart_Memory
*/
static void
AtSubStart_Memory(void)
{
TransactionState s = CurrentTransactionState;
Assert(CurTransactionContext != NULL);
/*
* Create a CurTransactionContext, which will be used to hold data that
* survives subtransaction commit but disappears on subtransaction abort.
* We make it a child of the immediate parent's CurTransactionContext.
*/
CurTransactionContext = AllocSetContextCreate(CurTransactionContext,
"CurTransactionContext",
ALLOCSET_DEFAULT_SIZES);
s->curTransactionContext = CurTransactionContext;
/* Make the CurTransactionContext active. */
MemoryContextSwitchTo(CurTransactionContext);
}
/*
* AtSubStart_ResourceOwner
*/
static void
AtSubStart_ResourceOwner(void)
{
TransactionState s = CurrentTransactionState;
Assert(s->parent != NULL);
/*
* Create a resource owner for the subtransaction. We make it a child of
* the immediate parent's resource owner.
*/
s->curTransactionOwner =
ResourceOwnerCreate(s->parent->curTransactionOwner,
"SubTransaction");
CurTransactionResourceOwner = s->curTransactionOwner;
CurrentResourceOwner = s->curTransactionOwner;
}
/* ----------------------------------------------------------------
* CommitTransaction stuff
* ----------------------------------------------------------------
*/
/*
* RecordTransactionCommit
*
* Returns latest XID among xact and its children, or InvalidTransactionId
* if the xact has no XID. (We compute that here just because it's easier.)
*
* If you change this function, see RecordTransactionCommitPrepared also.
*/
static TransactionId
RecordTransactionCommit(void)
{
TransactionId xid;
bool markXidCommitted;
TransactionId latestXid = InvalidTransactionId;
int nrels;
RelFileNodePendingDelete *rels;
DbDirNode *deldbs;
int ndeldbs;
int nchildren;
TransactionId *children;
int nmsgs = 0;
SharedInvalidationMessage *invalMessages = NULL;
bool RelcacheInitFileInval = false;
bool wrote_xlog;
bool isDtxPrepared = 0;
bool isOnePhaseQE = (Gp_role == GP_ROLE_EXECUTE && MyTmGxactLocal->isOnePhaseCommit);
/* Like in CommitTransaction(), treat a QE reader as if there was no XID */
if (DistributedTransactionContext == DTX_CONTEXT_QE_ENTRY_DB_SINGLETON ||
DistributedTransactionContext == DTX_CONTEXT_QE_READER)
{
xid = InvalidTransactionId;
}
else
xid = GetTopTransactionIdIfAny();
markXidCommitted = TransactionIdIsValid(xid);
/* Get data needed for commit record */
nrels = smgrGetPendingDeletes(true, &rels);
ndeldbs = GetPendingDbDeletes(true, &deldbs);
nchildren = xactGetCommittedChildren(&children);
if (XLogStandbyInfoActive())
nmsgs = xactGetCommittedInvalidationMessages(&invalMessages,
&RelcacheInitFileInval);
wrote_xlog = (XactLastRecEnd != 0);
isDtxPrepared = isPreparedDtxTransaction();
/*
* If we haven't been assigned an XID yet, we neither can, nor do we want
* to write a COMMIT record.
*/
if (!markXidCommitted)
{
/*
* We expect that every smgrscheduleunlink is followed by a catalog
* update, and hence XID assignment, so we shouldn't get here with any
* pending deletes. Use a real test not just an Assert to check this,
* since it's a bit fragile.
*/
if (nrels != 0)
elog(ERROR, "cannot commit a transaction that deleted files but has no xid");
/* Can't have child XIDs either; AssignTransactionId enforces this */
Assert(nchildren == 0);
/*
* Transactions without an assigned xid can contain invalidation
* messages (e.g. explicit relcache invalidations or catcache
* invalidations for inplace updates); standbys need to process those.
* We can't emit a commit record without an xid, and we don't want to
* force assigning an xid, because that'd be problematic for e.g.
* vacuum. Hence we emit a bespoke record for the invalidations. We
* don't want to use that in case a commit record is emitted, so they
* happen synchronously with commits (besides not wanting to emit more
* WAL records).
*/
if (nmsgs != 0)
{
LogStandbyInvalidations(nmsgs, invalMessages,
RelcacheInitFileInval);
wrote_xlog = true; /* not strictly necessary */
}
/*
* If we didn't create XLOG entries, we're done here; otherwise we
* should trigger flushing those entries the same as a commit record
* would. This will primarily happen for HOT pruning and the like; we
* want these to be flushed to disk in due time.
*/
if (!isDtxPrepared && !wrote_xlog)
goto cleanup;
}
/*
* A QD may write distributed commit record even when it didn't have a
* valid local XID if the distributed transaction changed data only on
* segments (e.g. DML statement).
*/
if (markXidCommitted || isDtxPrepared)
{
bool replorigin;
/*
* Are we using the replication origins feature? Or, in other words,
* are we replaying remote actions?
*/
replorigin = (replorigin_session_origin != InvalidRepOriginId &&
replorigin_session_origin != DoNotReplicateId);
/*
* Begin commit critical section and insert the commit XLOG record.
*/
/* Tell bufmgr and smgr to prepare for commit */
if (markXidCommitted)
BufmgrCommit();
if (isDtxPrepared)
SIMPLE_FAULT_INJECTOR("before_xlog_xact_distributed_commit");
/*
* Mark ourselves as within our "commit critical section". This
* forces any concurrent checkpoint to wait until we've updated
* pg_xact. Without this, it is possible for the checkpoint to set
* REDO after the XLOG record but fail to flush the pg_xact update to
* disk, leading to loss of the transaction commit if the system
* crashes a little later.
*
* Note: we could, but don't bother to, set this flag in
* RecordTransactionAbort. That's because loss of a transaction abort
* is noncritical; the presumption would be that it aborted, anyway.
*
* It's safe to change the delayChkpt flag of our own backend without
* holding the ProcArrayLock, since we're the only one modifying it.
* This makes checkpoint's determination of which xacts are delayChkpt
* a bit fuzzy, but it doesn't matter.
*
* In GPDB, if this is a distributed transaction, checkpoint process
* should hold off obtaining the REDO pointer while a backend is
* writing distributed commit xlog record and changing state of the
* distributed transaction. Otherwise, it is possible that a commit
* record is written by a transaction and the checkpointer determines
* REDO pointer to be after this commit record. But the transaction is
* yet to change its state to INSERTED_DISRIBUTED_COMMITTED and the
* checkpoint process fails to record this transaction in the
* checkpoint. Crash recovery will never see the commit record for
* this transaction and the second phase of 2PC will never happen. The
* delayChkpt flag avoids this situation by blocking checkpointer until a
* backend has finished updating the state.
*/
START_CRIT_SECTION();
MyPgXact->delayChkpt = true;
SetCurrentTransactionStopTimestamp();
SIMPLE_FAULT_INJECTOR("onephase_transaction_commit");
XactLogCommitRecord(xactStopTimestamp,
GetPendingTablespaceForDeletionForCommit(),
nchildren, children, nrels, rels,
nmsgs, invalMessages,
ndeldbs, deldbs,
RelcacheInitFileInval, forceSyncCommit,
MyXactFlags,
InvalidTransactionId, NULL /* plain commit */ );
if (replorigin)
/* Move LSNs forward for this replication origin */
replorigin_session_advance(replorigin_session_origin_lsn,
XactLastRecEnd);
/*
* Record commit timestamp. The value comes from plain commit
* timestamp if there's no replication origin; otherwise, the
* timestamp was already set in replorigin_session_origin_timestamp by
* replication.
*
* We don't need to WAL-log anything here, as the commit record
* written above already contains the data.
*/
if (!replorigin || replorigin_session_origin_timestamp == 0)
replorigin_session_origin_timestamp = xactStopTimestamp;
TransactionTreeSetCommitTsData(xid, nchildren, children,
replorigin_session_origin_timestamp,
replorigin_session_origin, false);
}
#ifdef IMPLEMENT_ASYNC_COMMIT
/*
* Check if we want to commit asynchronously. We can allow the XLOG flush
* to happen asynchronously if synchronous_commit=off, or if the current
* transaction has not performed any WAL-logged operation or didn't assign
* an xid. The transaction can end up not writing any WAL, even if it has
* an xid, if it only wrote to temporary and/or unlogged tables. It can
* end up having written WAL without an xid if it did HOT pruning. In
* case of a crash, the loss of such a transaction will be irrelevant;
* temp tables will be lost anyway, unlogged tables will be truncated and
* HOT pruning will be done again later. (Given the foregoing, you might
* think that it would be unnecessary to emit the XLOG record at all in
* this case, but we don't currently try to do that. It would certainly
* cause problems at least in Hot Standby mode, where the
* KnownAssignedXids machinery requires tracking every XID assignment. It
* might be OK to skip it only when wal_level < replica, but for now we
* don't.)
*
* In GPDB, however, all user transactions need to be committed synchronously,
* because we use two-phase commit across the nodes. In order to make GPDB support
* async-commit, we also need to implement the temp table detection.
*/
if ((wrote_xlog && markXidCommitted &&
synchronous_commit > SYNCHRONOUS_COMMIT_OFF) ||
forceSyncCommit || nrels > 0)
#endif
{
XLogFlush(XactLastRecEnd);
#ifdef FAULT_INJECTOR
if (isDtxPrepared == 0 &&
CurrentTransactionState->blockState == TBLOCK_END)
{
FaultInjector_InjectFaultIfSet("local_tm_record_transaction_commit",
DDLNotSpecified,
"", // databaseName
""); // tableName
}
#endif
/*
* Now we may update the CLOG, if we wrote a COMMIT record above
*/
if (markXidCommitted)
{
/*
* Mark the distributed transaction committed. Note that this
* is done *before* updating the clog. As soon as an XID is
* marked as comitted in the clog, other backends might try
* to look it up in the DistributedLog.
*/
/* UNDONE: What are the locking issues here? */
if (isDtxPrepared || isOnePhaseQE)
DistributedLog_SetCommittedTree(xid, nchildren, children,
getDistributedTransactionId(),
/* isRedo */ false);
TransactionIdCommitTree(xid, nchildren, children);
}
}
#ifdef IMPLEMENT_ASYNC_COMMIT
else
{
/*
* Asynchronous commit case:
*
* This enables possible committed transaction loss in the case of a
* postmaster crash because WAL buffers are left unwritten. Ideally we
* could issue the WAL write without the fsync, but some
* wal_sync_methods do not allow separate write/fsync.
*
* Report the latest async commit LSN, so that the WAL writer knows to
* flush this commit.
*/
XLogSetAsyncXactLSN(XactLastRecEnd);
/*
* We must not immediately update the CLOG, since we didn't flush the
* XLOG. Instead, we store the LSN up to which the XLOG must be
* flushed before the CLOG may be updated.
*/
if (markXidCommitted)
TransactionIdAsyncCommitTree(xid, nchildren, children, XactLastRecEnd);
}
#endif
#ifdef FAULT_INJECTOR
if (isDtxPrepared)
{
FaultInjector_InjectFaultIfSet("dtm_xlog_distributed_commit",
DDLNotSpecified,
"", // databaseName
""); // tableName
}
#endif
/*
* If we entered a commit critical section, leave it now, and let
* checkpoints proceed.
*/
if (markXidCommitted || isDtxPrepared)
{
MyPgXact->delayChkpt = false;
END_CRIT_SECTION();
SIMPLE_FAULT_INJECTOR("after_xlog_xact_distributed_commit");
}
/* Compute latestXid while we have the child XIDs handy */
latestXid = TransactionIdLatest(xid, nchildren, children);
/*
* Wait for synchronous replication, if required. Similar to the decision
* above about using committing asynchronously we only want to wait if
* this backend assigned an xid and wrote WAL. No need to wait if an xid
* was assigned due to temporary/unlogged tables or due to HOT pruning.
*
* Note that at this stage we have marked clog, but still show as running
* in the procarray and continue to hold locks.
*/
if ((wrote_xlog && markXidCommitted) || isDtxPrepared)
SyncRepWaitForLSN(XactLastRecEnd, true);
/* remember end of last commit record */
XactLastCommitEnd = XactLastRecEnd;
/* Reset XactLastRecEnd until the next transaction writes something */
XactLastRecEnd = 0;
cleanup:
/* And clean up local data */
return latestXid;
}
/*
* RecordDistributedForgetCommitted
*/
void
RecordDistributedForgetCommitted(DistributedTransactionId gxid)
{
xl_xact_distributed_forget xlrec;
xlrec.gxid = gxid;
XLogBeginInsert();
XLogRegisterData((char *) &xlrec, sizeof(xl_xact_distributed_forget));
XLogInsert(RM_XACT_ID, XLOG_XACT_DISTRIBUTED_FORGET);
}
/*
* AtCCI_LocalCache
*/
static void
AtCCI_LocalCache(void)
{
/*
* Make any pending relation map changes visible. We must do this before
* processing local sinval messages, so that the map changes will get
* reflected into the relcache when relcache invals are processed.
*/
AtCCI_RelationMap();
/*
* Make catalog changes visible to me for the next command.
*/
CommandEndInvalidationMessages();
}
/*
* AtCommit_Memory
*/
static void
AtCommit_Memory(void)
{
/*
* Now that we're "out" of a transaction, have the system allocate things
* in the top memory context instead of per-transaction contexts.
*/
MemoryContextSwitchTo(TopMemoryContext);
/*
* Release all transaction-local memory.
*/
Assert(TopTransactionContext != NULL);
MemoryContextDelete(TopTransactionContext);
TopTransactionContext = NULL;
CurTransactionContext = NULL;
CurrentTransactionState->curTransactionContext = NULL;
}
/* ----------------------------------------------------------------
* CommitSubTransaction stuff
* ----------------------------------------------------------------
*/
/*
* AtSubCommit_Memory
*/
static void
AtSubCommit_Memory(void)
{
TransactionState s = CurrentTransactionState;
Assert(s->parent != NULL);
/* Return to parent transaction level's memory context. */
CurTransactionContext = s->parent->curTransactionContext;
MemoryContextSwitchTo(CurTransactionContext);
/*
* Ordinarily we cannot throw away the child's CurTransactionContext,
* since the data it contains will be needed at upper commit. However, if
* there isn't actually anything in it, we can throw it away. This avoids
* a small memory leak in the common case of "trivial" subxacts.
*/
if (MemoryContextIsEmpty(s->curTransactionContext))
{
MemoryContextDelete(s->curTransactionContext);
s->curTransactionContext = NULL;
}
}
/*
* AtSubCommit_childXids
*
* Pass my own XID and my child XIDs up to my parent as committed children.
*/
static void
AtSubCommit_childXids(void)
{
TransactionState s = CurrentTransactionState;
int new_nChildXids;
Assert(s->parent != NULL);
/*
* The parent childXids array will need to hold my XID and all my
* childXids, in addition to the XIDs already there.
*/
new_nChildXids = s->parent->nChildXids + s->nChildXids + 1;
/* Allocate or enlarge the parent array if necessary */
if (s->parent->maxChildXids < new_nChildXids)
{
int new_maxChildXids;
TransactionId *new_childXids;
/*
* Make it 2x what's needed right now, to avoid having to enlarge it
* repeatedly. But we can't go above MaxAllocSize. (The latter limit
* is what ensures that we don't need to worry about integer overflow
* here or in the calculation of new_nChildXids.)
*/
new_maxChildXids = Min(new_nChildXids * 2,
(int) (MaxAllocSize / sizeof(TransactionId)));
if (new_maxChildXids < new_nChildXids)
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("maximum number of committed subtransactions (%d) exceeded",
(int) (MaxAllocSize / sizeof(TransactionId)))));
/*
* We keep the child-XID arrays in TopTransactionContext; this avoids
* setting up child-transaction contexts for what might be just a few
* bytes of grandchild XIDs.
*/
if (s->parent->childXids == NULL)
new_childXids =
MemoryContextAlloc(TopTransactionContext,
new_maxChildXids * sizeof(TransactionId));
else
new_childXids = repalloc(s->parent->childXids,
new_maxChildXids * sizeof(TransactionId));
s->parent->childXids = new_childXids;
s->parent->maxChildXids = new_maxChildXids;
}
/*
* Copy all my XIDs to parent's array.
*
* Note: We rely on the fact that the XID of a child always follows that
* of its parent. By copying the XID of this subtransaction before the
* XIDs of its children, we ensure that the array stays ordered. Likewise,
* all XIDs already in the array belong to subtransactions started and
* subcommitted before us, so their XIDs must precede ours.
*/
s->parent->childXids[s->parent->nChildXids] = XidFromFullTransactionId(s->fullTransactionId);
if (s->nChildXids > 0)
memcpy(&s->parent->childXids[s->parent->nChildXids + 1],
s->childXids,
s->nChildXids * sizeof(TransactionId));
s->parent->nChildXids = new_nChildXids;
/* Release child's array to avoid leakage */
if (s->childXids != NULL)
pfree(s->childXids);
/* We must reset these to avoid double-free if fail later in commit */
s->childXids = NULL;
s->nChildXids = 0;
s->maxChildXids = 0;
}
/* ----------------------------------------------------------------
* AbortTransaction stuff
* ----------------------------------------------------------------
*/
/*
* RecordTransactionAbort
*
* Returns latest XID among xact and its children, or InvalidTransactionId
* if the xact has no XID. (We compute that here just because it's easier.)
*/
static TransactionId
RecordTransactionAbort(bool isSubXact)
{
TransactionId xid;
TransactionId latestXid;
int nrels;
RelFileNodePendingDelete *rels;
int nchildren;
TransactionId *children;
TimestampTz xact_time;
DbDirNode *deldbs;
int ndeldbs;
bool isQEReader;
/* Like in CommitTransaction(), treat a QE reader as if there was no XID */
isQEReader = (DistributedTransactionContext == DTX_CONTEXT_QE_READER ||
DistributedTransactionContext == DTX_CONTEXT_QE_ENTRY_DB_SINGLETON);
/*
* Also, if an error occurred during distributed COMMIT processing, and
* we had already decided that we are going to commit this transaction and
* wrote a commit record for it, there's no turning back. The Distributed
* Transaction Manager will take care of completing the transaction for us.
*
* If the distributed transaction has started rolling back, it means we already
* wrote the abort record, skip it.
*/
if (isQEReader ||
getCurrentDtxState() == DTX_STATE_NOTIFYING_COMMIT_PREPARED ||
CurrentDtxIsRollingback() ||
MyProc->localDistribXactData.state == LOCALDISTRIBXACT_STATE_ABORTED)
xid = InvalidTransactionId;
else
xid = GetCurrentTransactionIdIfAny();
/*
* If we haven't been assigned an XID, nobody will care whether we aborted
* or not. Hence, we're done in that case. It does not matter if we have
* rels to delete (note that this routine is not responsible for actually
* deleting 'em). We cannot have any child XIDs, either.
*/
SetCurrentTransactionStopTimestamp();
if (!TransactionIdIsValid(xid))
{
/* Reset XactLastRecEnd until the next transaction writes something */
if (!isSubXact)
XactLastRecEnd = 0;
return InvalidTransactionId;
}
/*
* We have a valid XID, so we should write an ABORT record for it.
*
* We do not flush XLOG to disk here, since the default assumption after a
* crash would be that we aborted, anyway. For the same reason, we don't
* need to worry about interlocking against checkpoint start.
*/
/*
* Check that we haven't aborted halfway through RecordTransactionCommit.
*/
if (TransactionIdDidCommit(xid))
elog(PANIC, "cannot abort transaction %u, it was already committed",
xid);
/* Fetch the data we need for the abort record */
nrels = smgrGetPendingDeletes(false, &rels);
ndeldbs = GetPendingDbDeletes(false, &deldbs);
nchildren = xactGetCommittedChildren(&children);
/* XXX do we really need a critical section here? */
START_CRIT_SECTION();
/* Write the ABORT record */
if (isSubXact)
xact_time = GetCurrentTimestamp();
else
{
SetCurrentTransactionStopTimestamp();
xact_time = xactStopTimestamp;
}
XactLogAbortRecord(xact_time,
GetPendingTablespaceForDeletionForAbort(),
nchildren, children,
nrels, rels,
ndeldbs, deldbs,
MyXactFlags, InvalidTransactionId,
NULL);
/*
* Report the latest async abort LSN, so that the WAL writer knows to
* flush this abort. There's nothing to be gained by delaying this, since
* WALWriter may as well do this when it can. This is important with
* streaming replication because if we don't flush WAL regularly we will
* find that large aborts leave us with a long backlog for when commits
* occur after the abort, increasing our window of data loss should
* problems occur at that point.
*/
if (!isSubXact)
XLogSetAsyncXactLSN(XactLastRecEnd);
/*
* Mark the transaction aborted in clog. This is not absolutely necessary
* but we may as well do it while we are here; also, in the subxact case
* it is helpful because XactLockTableWait makes use of it to avoid
* waiting for already-aborted subtransactions. It is OK to do it without
* having flushed the ABORT record to disk, because in event of a crash
* we'd be assumed to have aborted anyway.
*/
TransactionIdAbortTree(xid, nchildren, children);
END_CRIT_SECTION();
/* Compute latestXid while we have the child XIDs handy */
latestXid = TransactionIdLatest(xid, nchildren, children);
/*
* If we're aborting a subtransaction, we can immediately remove failed
* XIDs from PGPROC's cache of running child XIDs. We do that here for
* subxacts, because we already have the child XID array at hand. For
* main xacts, the equivalent happens just after this function returns.
*/
if (isSubXact)
XidCacheRemoveRunningXids(xid, nchildren, children, latestXid);
/* Reset XactLastRecEnd until the next transaction writes something */
if (!isSubXact)
XactLastRecEnd = 0;
if (max_wal_senders > 0)
WalSndWakeup();
return latestXid;
}
/*
* AtAbort_Memory
*/
static void
AtAbort_Memory(void)
{
/*
* Switch into TransactionAbortContext, which should have some free space
* even if nothing else does. We'll work in this context until we've
* finished cleaning up.
*
* It is barely possible to get here when we've not been able to create
* TransactionAbortContext yet; if so use TopMemoryContext.
*/
if (TransactionAbortContext != NULL)
MemoryContextSwitchTo(TransactionAbortContext);
else
MemoryContextSwitchTo(TopMemoryContext);
}
/*
* AtSubAbort_Memory
*/
static void
AtSubAbort_Memory(void)
{
Assert(TransactionAbortContext != NULL);
MemoryContextSwitchTo(TransactionAbortContext);
}
/*
* AtAbort_ResourceOwner
*/
static void
AtAbort_ResourceOwner(void)
{
/*
* Make sure we have a valid ResourceOwner, if possible (else it will be
* NULL, which is OK)
*/
CurrentResourceOwner = TopTransactionResourceOwner;
}
/*
* AtSubAbort_ResourceOwner
*/
static void
AtSubAbort_ResourceOwner(void)
{
TransactionState s = CurrentTransactionState;
/* Make sure we have a valid ResourceOwner */
CurrentResourceOwner = s->curTransactionOwner;
}
/*
* AtSubAbort_childXids
*/
static void
AtSubAbort_childXids(void)
{
TransactionState s = CurrentTransactionState;
/*
* We keep the child-XID arrays in TopTransactionContext (see
* AtSubCommit_childXids). This means we'd better free the array
* explicitly at abort to avoid leakage.
*/
if (s->childXids != NULL)
pfree(s->childXids);
s->childXids = NULL;
s->nChildXids = 0;
s->maxChildXids = 0;
/*
* We could prune the unreportedXids array here. But we don't bother. That
* would potentially reduce number of XLOG_XACT_ASSIGNMENT records but it
* would likely introduce more CPU time into the more common paths, so we
* choose not to do that.
*/
}
/* ----------------------------------------------------------------
* CleanupTransaction stuff
* ----------------------------------------------------------------
*/
/*
* AtCleanup_Memory
*/
static void
AtCleanup_Memory(void)
{
Assert(CurrentTransactionState->parent == NULL);
/*
* Now that we're "out" of a transaction, have the system allocate things
* in the top memory context instead of per-transaction contexts.
*/
MemoryContextSwitchTo(TopMemoryContext);
/*
* Clear the special abort context for next time.
*/
if (TransactionAbortContext != NULL)
MemoryContextResetAndDeleteChildren(TransactionAbortContext);
/*
* Release all transaction-local memory.
*/
if (TopTransactionContext != NULL)
MemoryContextDelete(TopTransactionContext);
TopTransactionContext = NULL;
CurTransactionContext = NULL;
CurrentTransactionState->curTransactionContext = NULL;
}
/* ----------------------------------------------------------------
* CleanupSubTransaction stuff
* ----------------------------------------------------------------
*/
/*
* AtSubCleanup_Memory
*/
static void
AtSubCleanup_Memory(void)
{
TransactionState s = CurrentTransactionState;
Assert(s->parent != NULL);
/* Make sure we're not in an about-to-be-deleted context */
MemoryContextSwitchTo(s->parent->curTransactionContext);
CurTransactionContext = s->parent->curTransactionContext;
/*
* Clear the special abort context for next time.
*/
if (TransactionAbortContext != NULL)
MemoryContextResetAndDeleteChildren(TransactionAbortContext);
/*
* Delete the subxact local memory contexts. Its CurTransactionContext can
* go too (note this also kills CurTransactionContexts from any children
* of the subxact).
*/
if (s->curTransactionContext)
MemoryContextDelete(s->curTransactionContext);
s->curTransactionContext = NULL;
}
/* ----------------------------------------------------------------
* interface routines
* ----------------------------------------------------------------
*/
/* MPP routine for setting the transaction id. this is needed for the shared
* snapshot for segmates.
*
* TODO: this sucks to have to allow this since its potentially very dangerous.
* maybe we can re-factor the shared snapshot stuff differently to fix this.
* but unfortunately the XID and snapshot info is kept in two entirely different
* places so it doesn't look good.
*
* DOH: this totally ignores subtransactions for now!
*/
void
SetSharedTransactionId_writer(DtxContext distributedTransactionContext)
{
Assert(SharedLocalSnapshotSlot != NULL);
Assert(LWLockHeldByMe(SharedLocalSnapshotSlot->slotLock));
Assert(distributedTransactionContext == DTX_CONTEXT_QD_DISTRIBUTED_CAPABLE ||
distributedTransactionContext == DTX_CONTEXT_QE_TWO_PHASE_EXPLICIT_WRITER ||
distributedTransactionContext == DTX_CONTEXT_QE_TWO_PHASE_IMPLICIT_WRITER ||
distributedTransactionContext == DTX_CONTEXT_QE_AUTO_COMMIT_IMPLICIT);
ereportif(Debug_print_full_dtm, LOG,
(errmsg("%s setting shared xid " UINT64_FORMAT " -> " UINT64_FORMAT,
DtxContextToString(distributedTransactionContext),
U64FromFullTransactionId(SharedLocalSnapshotSlot->fullXid),
U64FromFullTransactionId(TopTransactionStateData.fullTransactionId))));
SharedLocalSnapshotSlot->fullXid = TopTransactionStateData.fullTransactionId;
}
void
SetSharedTransactionId_reader(FullTransactionId xid, CommandId cid, DtxContext distributedTransactionContext)
{
Assert(distributedTransactionContext == DTX_CONTEXT_QE_READER ||
distributedTransactionContext == DTX_CONTEXT_QE_ENTRY_DB_SINGLETON);
/*
* For DTX_CONTEXT_QE_READER or DTX_CONTEXT_QE_ENTRY_DB_SINGLETON, during
* StartTransaction(), currently we temporarily set the
* TopTransactionStateData.transactionId to what we find that time in
* SharedLocalSnapshot slot. Since, then QE writer could have moved-on and
* hence we reset the same to update to correct value here.
*/
TopTransactionStateData.fullTransactionId = xid;
currentCommandId = cid;
ereportif(Debug_print_full_dtm, LOG,
(errmsg("qExec READER setting local xid= " UINT64_FORMAT ", cid=%u "
"(distributedXid "UINT64_FORMAT"/%u)",
U64FromFullTransactionId(TopTransactionStateData.fullTransactionId), currentCommandId,
QEDtxContextInfo.distributedXid,
QEDtxContextInfo.segmateSync)));
}
/*
* StartTransaction
*/
static void
StartTransaction(void)
{
TransactionState s;
VirtualTransactionId vxid;
if (DistributedTransactionContext == DTX_CONTEXT_QE_ENTRY_DB_SINGLETON)
{
SIMPLE_FAULT_INJECTOR("transaction_start_under_entry_db_singleton");
}
/*
* Let's just make sure the state stack is empty
*/
s = &TopTransactionStateData;
CurrentTransactionState = s;
Assert(!FullTransactionIdIsValid(XactTopFullTransactionId));
/* check the current transaction state */
Assert(s->state == TRANS_DEFAULT);
/*
* Set the current transaction state information appropriately during
* start processing. Note that once the transaction status is switched
* this process cannot fail until the user ID and the security context
* flags are fetched below.
*/
s->state = TRANS_START;
s->fullTransactionId = InvalidFullTransactionId; /* until assigned */
/* Determine if statements are logged in this transaction */
xact_is_sampled = log_xact_sample_rate != 0 &&
(log_xact_sample_rate == 1 ||
random() <= log_xact_sample_rate * MAX_RANDOM_VALUE);
/*
* initialize current transaction state fields
*
* note: prevXactReadOnly is not used at the outermost level
*/
s->nestingLevel = 1;
s->gucNestLevel = 1;
s->childXids = NULL;
s->nChildXids = 0;
s->maxChildXids = 0;
/*
* Once the current user ID and the security context flags are fetched,
* both will be properly reset even if transaction startup fails.
*/
GetUserIdAndSecContext(&s->prevUser, &s->prevSecContext);
/* SecurityRestrictionContext should never be set outside a transaction */
Assert(s->prevSecContext == 0);
/*
* Make sure we've reset xact state variables
*
* If recovery is still in progress, mark this transaction as read-only.
* We have lower level defences in XLogInsert and elsewhere to stop us
* from modifying data during recovery, but this gives the normal
* indication to the user that the transaction is read-only.
*/
if (RecoveryInProgress())
{
s->startedInRecovery = true;
XactReadOnly = true;
}
else
{
s->startedInRecovery = false;
XactReadOnly = DefaultXactReadOnly;
}
XactDeferrable = DefaultXactDeferrable;
XactIsoLevel = DefaultXactIsoLevel;
forceSyncCommit = false;
seqXlogWrite = false;
MyXactFlags = 0;
/*
* reinitialize within-transaction counters
*/
s->subTransactionId = TopSubTransactionId;
currentSubTransactionId = TopSubTransactionId;
currentCommandId = FirstCommandId;
currentCommandIdUsed = false;
currentSavepointTotal = 0;
fastNodeCount = 0;
previousFastLink = NULL;
/*
* initialize reported xid accounting
*/
nUnreportedXids = 0;
s->didLogXid = false;
TopXactexecutorDidWriteXLog = false;
/*
* must initialize resource-management stuff first
*/
AtStart_Memory();
AtStart_ResourceOwner();
/*
* Transactions may be started while recovery is in progress, if
* hot standby is enabled. This mode is not supported in
* Greenplum yet.
*/
AssertImply(DistributedTransactionContext != DTX_CONTEXT_LOCAL_ONLY,
!s->startedInRecovery);
/*
* MPP Modification
*
* If we're an executor and don't have a valid QDSentXID, then we're starting
* a purely-local transaction.
*/
switch (DistributedTransactionContext)
{
case DTX_CONTEXT_LOCAL_ONLY:
case DTX_CONTEXT_QD_RETRY_PHASE_2:
case DTX_CONTEXT_QE_FINISH_PREPARED:
{
if (DistributedTransactionContext == DTX_CONTEXT_LOCAL_ONLY &&
Gp_role == GP_ROLE_UTILITY)
{
LocalDistribXactData *ele = &MyProc->localDistribXactData;
ele->state = LOCALDISTRIBXACT_STATE_ACTIVE;
}
/*
* MPP: we're in utility-mode or a QE starting a pure-local
* transaction without any synchronization to segmates!
* (e.g. CatchupInterruptHandler)
*/
}
break;
case DTX_CONTEXT_QD_DISTRIBUTED_CAPABLE:
{
if (SharedLocalSnapshotSlot != NULL)
{
LWLockAcquire(SharedLocalSnapshotSlot->slotLock, LW_EXCLUSIVE);
ereportif(Debug_print_full_dtm, LOG,
(errmsg("setting shared snapshot startTimestamp = "
INT64_FORMAT "[old=" INT64_FORMAT "])",
stmtStartTimestamp,
SharedLocalSnapshotSlot->startTimestamp)));
SharedLocalSnapshotSlot->startTimestamp = stmtStartTimestamp;
LWLockRelease(SharedLocalSnapshotSlot->slotLock);
}
LocalDistribXactData *ele = &MyProc->localDistribXactData;
ele->state = LOCALDISTRIBXACT_STATE_ACTIVE;
}
break;
case DTX_CONTEXT_QE_TWO_PHASE_EXPLICIT_WRITER:
case DTX_CONTEXT_QE_TWO_PHASE_IMPLICIT_WRITER:
case DTX_CONTEXT_QE_AUTO_COMMIT_IMPLICIT:
{
/* If we're running in test-mode insert a delay in writer. */
if (gp_enable_slow_writer_testmode)
pg_usleep(500000);
if (DistributedTransactionContext != DTX_CONTEXT_QE_AUTO_COMMIT_IMPLICIT &&
QEDtxContextInfo.distributedXid == InvalidDistributedTransactionId)
{
elog(ERROR,
"distributed transaction id is invalid in context %s",
DtxContextToString(DistributedTransactionContext));
}
/*
* Snapshot must not be created before setting transaction
* isolation level.
*/
Assert(!FirstSnapshotSet);
/* Assume transaction characteristics as sent by QD */
XactIsoLevel = mppTxOptions_IsoLevel(
QEDtxContextInfo.distributedTxnOptions);
XactReadOnly = isMppTxOptions_ReadOnly(
QEDtxContextInfo.distributedTxnOptions);
/*
* MPP: we're a QE Writer.
*/
MyTmGxact->gxid = QEDtxContextInfo.distributedXid;
if (DistributedTransactionContext ==
DTX_CONTEXT_QE_TWO_PHASE_EXPLICIT_WRITER ||
DistributedTransactionContext ==
DTX_CONTEXT_QE_TWO_PHASE_IMPLICIT_WRITER)
{
Assert(QEDtxContextInfo.distributedXid !=
InvalidDistributedTransactionId);
/*
* Update distributed XID info, this is only used for
* debugging.
*/
LocalDistribXactData *ele = &MyProc->localDistribXactData;
ele->distribXid = QEDtxContextInfo.distributedXid;
ele->state = LOCALDISTRIBXACT_STATE_ACTIVE;
}
if (SharedLocalSnapshotSlot != NULL)
{
LWLockAcquire(SharedLocalSnapshotSlot->slotLock, LW_EXCLUSIVE);
SharedLocalSnapshotSlot->ready = false;
SharedLocalSnapshotSlot->fullXid = s->fullTransactionId;
SharedLocalSnapshotSlot->startTimestamp = stmtStartTimestamp;
SharedLocalSnapshotSlot->distributedXid = QEDtxContextInfo.distributedXid;
SharedLocalSnapshotSlot->writer_proc = MyProc;
SharedLocalSnapshotSlot->writer_xact = MyPgXact;
ereportif(Debug_print_full_dtm, LOG,
(errmsg(
"qExec writer setting distributedXid: "UINT64_FORMAT
" sharedQDxid (shared xid " UINT64_FORMAT " -> " UINT64_FORMAT ") ready %s"
" (shared timeStamp = " INT64_FORMAT " -> "
INT64_FORMAT ")",
SharedLocalSnapshotSlot->distributedXid,
U64FromFullTransactionId(SharedLocalSnapshotSlot->fullXid),
U64FromFullTransactionId(s->fullTransactionId),
SharedLocalSnapshotSlot->ready ? "true" : "false",
SharedLocalSnapshotSlot->startTimestamp,
xactStartTimestamp)));
LWLockRelease(SharedLocalSnapshotSlot->slotLock);
}
}
break;
case DTX_CONTEXT_QE_ENTRY_DB_SINGLETON:
case DTX_CONTEXT_QE_READER:
{
/*
* MPP: we're a QE Reader.
*/
Assert (SharedLocalSnapshotSlot != NULL);
MyTmGxact->gxid = QEDtxContextInfo.distributedXid;
/*
* Snapshot must not be created before setting transaction
* isolation level.
*/
Assert(!FirstSnapshotSet);
/* Assume transaction characteristics as sent by QD */
XactIsoLevel = mppTxOptions_IsoLevel(
QEDtxContextInfo.distributedTxnOptions);
XactReadOnly = isMppTxOptions_ReadOnly(
QEDtxContextInfo.distributedTxnOptions);
if (unlikely(Debug_print_full_dtm))
{
LWLockAcquire(SharedSnapshotLock, LW_SHARED); /* For SharedSnapshotDump() */
ereport(LOG, (errmsg("qExec reader: distributedXid "UINT64_FORMAT" currcid %d "
"gxid = "UINT64_FORMAT" DtxContext '%s' sharedsnapshots: %s",
QEDtxContextInfo.distributedXid,
QEDtxContextInfo.curcid,
getDistributedTransactionId(),
DtxContextToString(DistributedTransactionContext),
SharedSnapshotDump())));
LWLockRelease(SharedSnapshotLock);
}
}
break;
case DTX_CONTEXT_QE_PREPARED:
elog(FATAL, "Unexpected segment distribute transaction context: '%s'",
DtxContextToString(DistributedTransactionContext));
break;
default:
elog(PANIC, "Unrecognized DTX transaction context: %d",
(int) DistributedTransactionContext);
break;
}
ereportif(Debug_print_snapshot_dtm, LOG,
(errmsg("[Distributed Snapshot #%u] *StartTransaction* "
"(gxid = "UINT64_FORMAT", xid = " UINT64_FORMAT ", '%s')",
(!FirstSnapshotSet ? 0 :
GetTransactionSnapshot()->
distribSnapshotWithLocalMapping.ds.distribSnapshotId),
getDistributedTransactionId(),
U64FromFullTransactionId(s->fullTransactionId),
DtxContextToString(DistributedTransactionContext))));
/*
* Assign a new LocalTransactionId, and combine it with the backendId to
* form a virtual transaction id.
*/
vxid.backendId = MyBackendId;
vxid.localTransactionId = GetNextLocalTransactionId();
/*
* Lock the virtual transaction id before we announce it in the proc array
*/
VirtualXactLockTableInsert(vxid);
/*
* Advertise it in the proc array. We assume assignment of
* LocalTransactionID is atomic, and the backendId should be set already.
*/
Assert(MyProc->backendId == vxid.backendId);
MyProc->lxid = vxid.localTransactionId;
TRACE_POSTGRESQL_TRANSACTION_START(vxid.localTransactionId);
/*
* set transaction_timestamp() (a/k/a now()). Normally, we want this to
* be the same as the first command's statement_timestamp(), so don't do a
* fresh GetCurrentTimestamp() call (which'd be expensive anyway). But
* for transactions started inside procedures (i.e., nonatomic SPI
* contexts), we do need to advance the timestamp. Also, in a parallel
* worker, the timestamp should already have been provided by a call to
* SetParallelStartTimestamps().
*/
if (!IsParallelWorker())
{
if (!SPI_inside_nonatomic_context())
xactStartTimestamp = stmtStartTimestamp;
else
xactStartTimestamp = GetCurrentTimestamp();
}
else
Assert(xactStartTimestamp != 0);
pgstat_report_xact_timestamp(xactStartTimestamp);
/* Mark xactStopTimestamp as unset. */
xactStopTimestamp = 0;
/*
* initialize other subsystems for new transaction
*/
AtStart_GUC();
AtStart_Cache();
AfterTriggerBeginXact();
/*
* done with start processing, set current transaction state to "in
* progress"
*/
s->state = TRANS_INPROGRESS;
/*
* Update the snapshot of gp_segment_configuration, it's not changed
* until the end of transaction, do this update inside a transaction
* because it does a catalog lookup.
*
* Sometimes, a new transaction is started before first access to db,
* however, reading a catalog like gp_segment_configuration need a
* database be selected. In such case, we disallow updating the snapshot
* of segments configuration.
*/
if (Gp_role == GP_ROLE_DISPATCH && OidIsValid(MyDatabaseId))
cdbcomponent_updateCdbComponents();
/*
* Acquire a resource group slot.
*
* Slot is successfully acquired when AssignResGroupOnMaster() is returned.
* This slot will be released when the transaction is committed or aborted.
*
* Note that AssignResGroupOnMaster() can throw a PG exception. Since we
* have set the transaction state to TRANS_INPROGRESS by this point, any
* exceptions thrown will trigger AbortTransaction() and free the slot.
*
* It's important that we acquire the resource group *after* starting the
* transaction (i.e. setting up the per-transaction memory context).
* As part of determining the resource group that the transaction should be
* assigned to, AssignResGroupOnMaster() accesses pg_authid, and a
* transaction should be in progress when it does so.
*/
if (ShouldAssignResGroupOnMaster())
AssignResGroupOnMaster();
initialize_wal_bytes_written();
ShowTransactionState("StartTransaction");
ereportif(Debug_print_full_dtm, LOG,
(errmsg("StartTransaction in DTX Context = '%s', "
"isolation level %s, read-only = %d, %s",
DtxContextToString(DistributedTransactionContext),
IsoLevelAsUpperString(XactIsoLevel), XactReadOnly,
LocalDistribXact_DisplayString(MyProc->pgprocno))));
}
/*
* CommitTransaction
*
* NB: if you change this routine, better look at PrepareTransaction too!
*/
static void
CommitTransaction(void)
{
TransactionState s = CurrentTransactionState;
TransactionId latestXid;
bool is_parallel_worker;
is_parallel_worker = (s->blockState == TBLOCK_PARALLEL_INPROGRESS);
/* Enforce parallel mode restrictions during parallel worker commit. */
if (is_parallel_worker)
EnterParallelMode();
ShowTransactionState("CommitTransaction");
/*
* check the current transaction state
*/
if (s->state != TRANS_INPROGRESS)
elog(WARNING, "CommitTransaction while in %s state",
TransStateAsString(s->state));
Assert(s->parent == NULL);
if (Gp_role == GP_ROLE_EXECUTE && !Gp_is_writer)
elog(DEBUG1,"CommitTransaction: called as segment Reader");
/*
* Do pre-commit processing that involves calling user-defined code, such
* as triggers. SECURITY_RESTRICTED_OPERATION contexts must not queue an
* action that would run here, because that would bypass the sandbox.
* Since closing cursors could queue trigger actions, triggers could open
* cursors, etc, we have to keep looping until there's nothing left to do.
*/
for (;;)
{
/*
* Fire all currently pending deferred triggers.
*/
AfterTriggerFireDeferred();
/*
* Close open portals (converting holdable ones into static portals).
* If there weren't any, we are done ... otherwise loop back to check
* if they queued deferred triggers. Lather, rinse, repeat.
*/
if (!PreCommit_Portals(false))
break;
}
/*
* The remaining actions cannot call any user-defined code, so it's safe
* to start shutting down within-transaction services. But note that most
* of this stuff could still throw an error, which would switch us into
* the transaction-abort path.
*/
CallXactCallbacks(is_parallel_worker ? XACT_EVENT_PARALLEL_PRE_COMMIT
: XACT_EVENT_PRE_COMMIT);
/* If we might have parallel workers, clean them up now. */
if (IsInParallelMode())
AtEOXact_Parallel(true);
/* Shut down the deferred-trigger manager */
AfterTriggerEndXact(true);
AtEOXact_SharedSnapshot();
/* Perform any Resource Scheduler commit procesing. */
if (Gp_role == GP_ROLE_DISPATCH && IsResQueueEnabled())
AtCommit_ResScheduler();
/*
* Let ON COMMIT management do its thing (must happen after closing
* cursors, to avoid dangling-reference problems)
*/
PreCommit_on_commit_actions();
/* This can still fail */
AtEOXact_DispatchOids(true);
/* close large objects before lower-level cleanup */
AtEOXact_LargeObject(true);
/*
* Mark serializable transaction as complete for predicate locking
* purposes. This should be done as late as we can put it and still allow
* errors to be raised for failure patterns found at commit. This is not
* appropriate in a parallel worker however, because we aren't committing
* the leader's transaction and its serializable state will live on.
*/
if (!is_parallel_worker)
PreCommit_CheckForSerializationFailure();
/*
* Insert notifications sent by NOTIFY commands into the queue. This
* should be late in the pre-commit sequence to minimize time spent
* holding the notify-insertion lock.
*/
PreCommit_Notify();
/*
* Prepare all QE.
*/
prepareDtxTransaction();
#ifdef FAULT_INJECTOR
if (isPreparedDtxTransaction())
{
FaultInjector_InjectFaultIfSet(
"transaction_abort_after_distributed_prepared",
DDLNotSpecified,
"", // databaseName
""); // tableName
}
#endif
if (Debug_abort_after_distributed_prepared &&
isPreparedDtxTransaction())
{
ereport(ERROR,
(errcode(ERRCODE_FAULT_INJECT),
errmsg("Raise an error as directed by Debug_abort_after_distributed_prepared")));
}
/* Prevent cancel/die interrupt while cleaning up */
HOLD_INTERRUPTS();
/* Commit updates to the relation map --- do this as late as possible */
AtEOXact_RelationMap(true, is_parallel_worker);
/*
* set the current transaction state information appropriately during
* commit processing
*/
s->state = TRANS_COMMIT;
s->parallelModeLevel = 0;
if (!is_parallel_worker)
{
/*
* We need to mark our XIDs as committed in pg_xact. This is where we
* durably commit.
*/
latestXid = RecordTransactionCommit();
}
else
{
/*
* We must not mark our XID committed; the parallel master is
* responsible for that.
*/
latestXid = InvalidTransactionId;
/*
* Make sure the master will know about any WAL we wrote before it
* commits.
*/
ParallelWorkerReportLastRecEnd(XactLastRecEnd);
}
TRACE_POSTGRESQL_TRANSACTION_COMMIT(MyProc->lxid);
/*
* Do 2nd phase of commit to all QE. NOTE: we can't process
* signals (which may attempt to abort our now partially-completed
* transaction) until we've notified the QEs.
*
* Very important that PGPROC still thinks the transaction is still in progress so
* SnapshotNow reader don't jump to the conclusion this distributed transaction is
* finished. So, notifyCommittedDtxTransaction will take responsbility to clear
* PGPROC under the ProcArrayLock after the broadcast. MPP-16087.
*
* And, that we have not master released locks, yet, too.
*
* Note: do this BEFORE clearing the resource owner, as the dispatch
* routines might want to use them. Plus, we want AtCommit_Memory to
* happen after using the dispatcher.
*/
if (notifyCommittedDtxTransactionIsNeeded())
notifyCommittedDtxTransaction();
/*
* Let others know about no transaction in progress by me. Note that this
* must be done _before_ releasing locks we hold and _after_
* RecordTransactionCommit.
*/
ProcArrayEndTransaction(MyProc, latestXid);
EndLocalDistribXact(true);
/*
* This is all post-commit cleanup. Note that if an error is raised here,
* it's too late to abort the transaction. This should be just
* noncritical resource releasing.
*
* The ordering of operations is not entirely random. The idea is:
* release resources visible to other backends (eg, files, buffer pins);
* then release locks; then release backend-local resources. We want to
* release locks at the point where any backend waiting for us will see
* our transaction as being fully cleaned up.
*
* Resources that can be associated with individual queries are handled by
* the ResourceOwner mechanism. The other calls here are for backend-wide
* state.
*/
CallXactCallbacks(is_parallel_worker ? XACT_EVENT_PARALLEL_COMMIT
: XACT_EVENT_COMMIT);
CallXactCallbacksOnce(XACT_EVENT_COMMIT);
ResourceOwnerRelease(TopTransactionResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
true, true);
/* detach combocid dsm */
AtEOXact_ComboCid_Dsm_Detach();
/* Check we've released all buffer pins */
AtEOXact_Buffers(true);
/* Clean up the relation cache */
AtEOXact_RelationCache(true);
/*
* Make catalog changes visible to all backends. This has to happen after
* relcache references are dropped (see comments for
* AtEOXact_RelationCache), but before locks are released (if anyone is
* waiting for lock on a relation we've modified, we want them to know
* about the catalog change before they start using the relation).
*/
AtEOXact_Inval(true);
AtEOXact_MultiXact();
ResourceOwnerRelease(TopTransactionResourceOwner,
RESOURCE_RELEASE_LOCKS,
true, true);
ResourceOwnerRelease(TopTransactionResourceOwner,
RESOURCE_RELEASE_AFTER_LOCKS,
true, true);
/*
* Likewise, dropping of files deleted during the transaction is best done
* after releasing relcache and buffer pins. (This is not strictly
* necessary during commit, since such pins should have been released
* already, but this ordering is definitely critical during abort.) Since
* this may take many seconds, also delay until after releasing locks.
* Other backends will observe the attendant catalog changes and not
* attempt to access affected files.
*
* Same considerations for tablespace deletion
*/
smgrDoPendingDeletes(true);
DoPendingDbDeletes(true);
/*
* Only QD holds the session level lock this long for a movedb operation.
* This is to prevent another transaction from moving database objects into
* the source database oid directory while it is being deleted. We don't
* worry about aborts as we release session level locks automatically during
* an abort as opposed to a commit.
*/
if(Gp_role == GP_ROLE_DISPATCH)
MoveDbSessionLockRelease();
AtCommit_TablespaceStorage();
AtCommit_Notify();
AtEOXact_GUC(true, 1);
AtEOXact_SPI(true);
AtEOXact_Enum();
AtEOXact_on_commit_actions(true);
AtEOXact_Namespace(true, is_parallel_worker);
AtEOXact_SMgr();
AtEOXact_Files(true);
AtEOXact_ComboCid();
AtEOXact_HashTables(true);
AtEOXact_PgStat(true, is_parallel_worker);
AtEOXact_Snapshot(true, false);
AtEOXact_ApplyLauncher(true);
AtEOXact_WorkFile();
pgstat_report_xact_timestamp(0);
CurrentResourceOwner = NULL;
ResourceOwnerDelete(TopTransactionResourceOwner);
s->curTransactionOwner = NULL;
CurTransactionResourceOwner = NULL;
TopTransactionResourceOwner = NULL;
AtCommit_Memory();
finishDistributedTransactionContext("CommitTransaction", false);
if (gp_local_distributed_cache_stats)
{
LocalDistribXactCache_ShowStats("CommitTransaction");
}
s->fullTransactionId = InvalidFullTransactionId;
s->subTransactionId = InvalidSubTransactionId;
s->nestingLevel = 0;
s->gucNestLevel = 0;
s->childXids = NULL;
s->nChildXids = 0;
s->maxChildXids = 0;
s->executorSaysXactDoesWrites = false;
XactTopFullTransactionId = InvalidFullTransactionId;
nParallelCurrentXids = 0;
/*
* done with commit processing, set current transaction state back to
* default
*/
s->state = TRANS_DEFAULT;
/* we're now in a consistent state to handle an interrupt. */
RESUME_INTERRUPTS();
/* Release resource group slot at the end of a transaction */
if (ShouldUnassignResGroup())
UnassignResGroup(false);
}
/*
* PrepareTransaction
*
* NB: if you change this routine, better look at CommitTransaction too!
*/
static void
PrepareTransaction(void)
{
TransactionState s = CurrentTransactionState;
TransactionId xid = GetCurrentTransactionId();
GlobalTransaction gxact;
TimestampTz prepared_at;
Assert(!IsInParallelMode());
ShowTransactionState("PrepareTransaction");
/*
* check the current transaction state
*/
if (s->state != TRANS_INPROGRESS)
elog(WARNING, "PrepareTransaction while in %s state",
TransStateAsString(s->state));
Assert(s->parent == NULL);
/*
* Do pre-commit processing that involves calling user-defined code, such
* as triggers. Since closing cursors could queue trigger actions,
* triggers could open cursors, etc, we have to keep looping until there's
* nothing left to do.
*/
for (;;)
{
/*
* Fire all currently pending deferred triggers.
*/
AfterTriggerFireDeferred();
/*
* Close open portals (converting holdable ones into static portals).
* If there weren't any, we are done ... otherwise loop back to check
* if they queued deferred triggers. Lather, rinse, repeat.
*/
if (!PreCommit_Portals(true))
break;
}
CallXactCallbacks(XACT_EVENT_PRE_PREPARE);
/*
* The remaining actions cannot call any user-defined code, so it's safe
* to start shutting down within-transaction services. But note that most
* of this stuff could still throw an error, which would switch us into
* the transaction-abort path.
*/
/* Shut down the deferred-trigger manager */
AfterTriggerEndXact(true);
/*
* Let ON COMMIT management do its thing (must happen after closing
* cursors, to avoid dangling-reference problems)
*/
PreCommit_on_commit_actions();
AtEOXact_DispatchOids(true);
/* close large objects before lower-level cleanup */
AtEOXact_LargeObject(true);
/*
* Mark serializable transaction as complete for predicate locking
* purposes. This should be done as late as we can put it and still allow
* errors to be raised for failure patterns found at commit.
*/
PreCommit_CheckForSerializationFailure();
/* NOTIFY will be handled below */
/*
* In Postgres, XACT_FLAGS_ACCESSEDTEMPNAMESPACE is used to error out if
* PREPARE TRANSACTION operated on temp table.
*
* In GPDB, XACT_FLAGS_ACCESSEDTEMPNAMESPACE is removed.
*
* GPDB treat temporary table like a regular table, e.g. stored in shared buffer
* instead of keep it in local buffer. The temporary table just have a shorter life
* cycle either tie to the session or tie to the transaction if ON COMMIT clause is
* used.
*
* Every transaction in GPDB is 2PC, so PREPARE TRANSACTION is used even for temp table
* creation. GPDB cannot error out, otherwise, it won't be able to handle temp table
* at all.
*/
#if 0 /* Upstream code not applicable to GPDB */
/*
* Don't allow PREPARE TRANSACTION if we've accessed a temporary table in
* this transaction. Having the prepared xact hold locks on another
* backend's temp table seems a bad idea --- for instance it would prevent
* the backend from exiting. There are other problems too, such as how to
* clean up the source backend's local buffers and ON COMMIT state if the
* prepared xact includes a DROP of a temp table.
*
* Other objects types, like functions, operators or extensions, share the
* same restriction as they should not be created, locked or dropped as
* this can mess up with this session or even a follow-up session trying
* to use the same temporary namespace.
*
* We must check this after executing any ON COMMIT actions, because they
* might still access a temp relation.
*
* XXX In principle this could be relaxed to allow some useful special
* cases, such as a temp table created and dropped all within the
* transaction. That seems to require much more bookkeeping though.
*/
if ((MyXactFlags & XACT_FLAGS_ACCESSEDTEMPNAMESPACE))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot PREPARE a transaction that has operated on temporary objects")));
#endif
SIMPLE_FAULT_INJECTOR("start_prepare");
/*
* Likewise, don't allow PREPARE after pg_export_snapshot. This could be
* supported if we added cleanup logic to twophase.c, but for now it
* doesn't seem worth the trouble.
*/
if (XactHasExportedSnapshots())
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot PREPARE a transaction that has exported snapshots")));
/*
* Don't allow PREPARE but for transaction that has/might kill logical
* replication workers.
*/
if (XactManipulatesLogicalReplicationWorkers())
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot PREPARE a transaction that has manipulated logical replication workers")));
/* Prevent cancel/die interrupt while cleaning up */
HOLD_INTERRUPTS();
/* Do some preparaty work on locks, before we change the transaction state. */
PrePrepare_Locks();
/*
* set the current transaction state information appropriately during
* prepare processing
*/
s->state = TRANS_PREPARE;
prepared_at = GetCurrentTimestamp();
/* Tell bufmgr and smgr to prepare for commit */
BufmgrCommit();
/*
* We cannot prepare if the xid is already aborted for some reason.
* If we proceed with this unexpected state, we'll be unrecoverable.
*/
if (TransactionIdDidAbort(xid))
elog(ERROR, "xid %u is already aborted", xid);
/*
* Reserve the GID for this transaction. This could fail if the requested
* GID is invalid or already in use.
*/
gxact = MarkAsPreparing(xid, &MyProc->localDistribXactData,
prepareGID, prepared_at,
GetUserId(), MyDatabaseId);
prepareGID = NULL;
/*
* Collect data for the 2PC state file. Note that in general, no actual
* state change should happen in the called modules during this step,
* since it's still possible to fail before commit, and in that case we
* want transaction abort to be able to clean up. (In particular, the
* AtPrepare routines may error out if they find cases they cannot
* handle.) State cleanup should happen in the PostPrepare routines
* below. However, some modules can go ahead and clear state here because
* they wouldn't do anything with it during abort anyway.
*
* Note: because the 2PC state file records will be replayed in the same
* order they are made, the order of these calls has to match the order in
* which we want things to happen during COMMIT PREPARED or ROLLBACK
* PREPARED; in particular, pay attention to whether things should happen
* before or after releasing the transaction's locks.
*/
StartPrepare(gxact);
AtPrepare_Notify();
AtPrepare_Locks();
AtPrepare_PredicateLocks();
AtPrepare_PgStat();
AtPrepare_MultiXact();
AtPrepare_RelationMap();
/*
* Here is where we really truly prepare.
*
* We have to record transaction prepares even if we didn't make any
* updates, because the transaction manager might get confused if we lose
* a global transaction.
*/
EndPrepare(gxact);
/*
* Now we clean up backend-internal state and release internal resources.
*/
/* Reset XactLastRecEnd until the next transaction writes something */
XactLastRecEnd = 0;
/*
* Let others know about no transaction in progress by me. This has to be
* done *after* the prepared transaction has been marked valid, else
* someone may think it is unlocked and recyclable.
*/
LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
ProcArrayClearTransaction(MyProc);
LWLockRelease(ProcArrayLock);
/*
* In normal commit-processing, this is all non-critical post-transaction
* cleanup. When the transaction is prepared, however, it's important
* that the locks and other per-backend resources are transferred to the
* prepared transaction's PGPROC entry. Note that if an error is raised
* here, it's too late to abort the transaction. XXX: This probably should
* be in a critical section, to force a PANIC if any of this fails, but
* that cure could be worse than the disease.
*/
CallXactCallbacks(XACT_EVENT_PREPARE);
CallXactCallbacksOnce(XACT_EVENT_PREPARE);
ResourceOwnerRelease(TopTransactionResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
true, true);
/* detach combocid dsm */
AtEOXact_ComboCid_Dsm_Detach();
/* Check we've released all buffer pins */
AtEOXact_Buffers(true);
/* Clean up the relation cache */
AtEOXact_RelationCache(true);
/* notify doesn't need a postprepare call */
PostPrepare_PgStat();
PostPrepare_Inval();
PostPrepare_smgr();
PostPrepare_DatabaseStorage();
PostPrepare_MultiXact(xid);
PostPrepare_Locks(xid);
PostPrepare_PredicateLocks(xid);
ResourceOwnerRelease(TopTransactionResourceOwner,
RESOURCE_RELEASE_LOCKS,
true, true);
ResourceOwnerRelease(TopTransactionResourceOwner,
RESOURCE_RELEASE_AFTER_LOCKS,
true, true);
/*
* Allow another backend to finish the transaction. After
* PostPrepare_Twophase(), the transaction is completely detached from our
* backend. The rest is just non-critical cleanup of backend-local state.
*/
PostPrepare_Twophase();
/* PREPARE acts the same as COMMIT as far as GUC is concerned */
AtEOXact_GUC(true, 1);
AtEOXact_SPI(true);
AtEOXact_Enum();
AtEOXact_on_commit_actions(true);
AtEOXact_Namespace(true, false);
AtEOXact_SMgr();
AtEOXact_Files(true);
AtEOXact_ComboCid();
AtEOXact_HashTables(true);
/* don't call AtEOXact_PgStat here; we fixed pgstat state above */
AtEOXact_Snapshot(true, true);
AtEOXact_WorkFile();
pgstat_report_xact_timestamp(0);
CurrentResourceOwner = NULL;
ResourceOwnerDelete(TopTransactionResourceOwner);
s->curTransactionOwner = NULL;
CurTransactionResourceOwner = NULL;
TopTransactionResourceOwner = NULL;
AtCommit_Memory();
if (gp_local_distributed_cache_stats)
{
LocalDistribXactCache_ShowStats("PrepareTransaction");
}
s->fullTransactionId = InvalidFullTransactionId;
s->subTransactionId = InvalidSubTransactionId;
s->nestingLevel = 0;
s->gucNestLevel = 0;
s->childXids = NULL;
s->nChildXids = 0;
s->maxChildXids = 0;
s->executorSaysXactDoesWrites = false;
XactTopFullTransactionId = InvalidFullTransactionId;
nParallelCurrentXids = 0;
/*
* done with 1st phase commit processing, set current transaction state
* back to default
*/
s->state = TRANS_DEFAULT;
RESUME_INTERRUPTS();
/* Release resource group slot at the end of prepare transaction on segment */
if (ShouldUnassignResGroup())
UnassignResGroup(false);
}
/*
* AbortTransaction
*/
static void
AbortTransaction(void)
{
TransactionState s = CurrentTransactionState;
TransactionId latestXid;
bool is_parallel_worker;
SIMPLE_FAULT_INJECTOR("transaction_abort_failure");
/* Prevent cancel/die interrupt while cleaning up */
HOLD_INTERRUPTS();
/* Make sure we have a valid memory context and resource owner */
AtAbort_Memory();
if (Gp_role == GP_ROLE_EXECUTE)
ResetExtensionCreatingGlobalVarsOnQE();
AtAbort_ResourceOwner();
/*
* Release any LW locks we might be holding as quickly as possible.
* (Regular locks, however, must be held till we finish aborting.)
* Releasing LW locks is critical since we might try to grab them again
* while cleaning up!
*/
LWLockReleaseAll();
/* Clear wait information and command progress indicator */
pgstat_report_wait_end();
pgstat_progress_end_command();
/* Clean up buffer I/O and buffer context locks, too */
AbortBufferIO();
UnlockBuffers();
/* Reset WAL record construction state */
XLogResetInsertion();
/* Cancel condition variable sleep */
ConditionVariableCancelSleep();
/*
* Also clean up any open wait for lock, since the lock manager will choke
* if we try to wait for another lock before doing this.
*/
LockErrorCleanup();
/*
* If any timeout events are still active, make sure the timeout interrupt
* is scheduled. This covers possible loss of a timeout interrupt due to
* longjmp'ing out of the SIGINT handler (see notes in handle_sig_alarm).
* We delay this till after LockErrorCleanup so that we don't uselessly
* reschedule lock or deadlock check timeouts.
*/
reschedule_timeouts();
/*
* Re-enable signals, in case we got here by longjmp'ing out of a signal
* handler. We do this fairly early in the sequence so that the timeout
* infrastructure will be functional if needed while aborting.
*/
PG_SETMASK(&UnBlockSig);
/*
* check the current transaction state
*/
is_parallel_worker = (s->blockState == TBLOCK_PARALLEL_INPROGRESS);
if (s->state != TRANS_INPROGRESS && s->state != TRANS_PREPARE)
elog(DEBUG1, "WARNING: AbortTransaction while in %s state",
TransStateAsString(s->state));
Assert(s->parent == NULL);
/*
* set the current transaction state information appropriately during the
* abort processing
*/
s->state = TRANS_ABORT;
/*
* Reset user ID which might have been changed transiently. We need this
* to clean up in case control escaped out of a SECURITY DEFINER function
* or other local change of CurrentUserId; therefore, the prior value of
* SecurityRestrictionContext also needs to be restored.
*
* (Note: it is not necessary to restore session authorization or role
* settings here because those can only be changed via GUC, and GUC will
* take care of rolling them back if need be.)
*/
SetUserIdAndSecContext(s->prevUser, s->prevSecContext);
/* If in parallel mode, clean up workers and exit parallel mode. */
if (IsInParallelMode())
{
AtEOXact_Parallel(false);
s->parallelModeLevel = 0;
}
/*
* do abort processing
*/
AfterTriggerEndXact(false); /* 'false' means it's abort */
AtAbort_EndpointExecState();
AtAbort_Portals();
AtAbort_DispatcherState();
AtEOXact_SharedSnapshot();
/* Perform any Resource Scheduler abort procesing. */
if (Gp_role == GP_ROLE_DISPATCH && IsResQueueEnabled())
AtAbort_ResScheduler();
AtEOXact_DispatchOids(false);
AtEOXact_LargeObject(false);
AtAbort_Notify();
AtEOXact_RelationMap(false, is_parallel_worker);
AtAbort_Twophase();
/*
* Advertise the fact that we aborted in pg_xact (assuming that we got as
* far as assigning an XID to advertise). But if we're inside a parallel
* worker, skip this; the user backend must be the one to write the abort
* record.
*/
if (!is_parallel_worker)
latestXid = RecordTransactionAbort(false);
else
{
latestXid = InvalidTransactionId;
/*
* Since the parallel master won't get our value of XactLastRecEnd in
* this case, we nudge WAL-writer ourselves in this case. See related
* comments in RecordTransactionAbort for why this matters.
*/
XLogSetAsyncXactLSN(XactLastRecEnd);
}
TRACE_POSTGRESQL_TRANSACTION_ABORT(MyProc->lxid);
/*
* Do abort to all QE. NOTE: we don't process
* signals to prevent recursion until we've notified the QEs.
*/
rollbackDtxTransaction();
/*
* Let others know about no transaction in progress by me. Note that this
* must be done _before_ releasing locks we hold and _after_
* RecordTransactionAbort.
*/
ProcArrayEndTransaction(MyProc, latestXid);
EndLocalDistribXact(false);
SIMPLE_FAULT_INJECTOR("abort_after_procarray_end");
/*
* Post-abort cleanup. See notes in CommitTransaction() concerning
* ordering. We can skip all of it if the transaction failed before
* creating a resource owner.
*/
if (TopTransactionResourceOwner != NULL)
{
if (is_parallel_worker)
CallXactCallbacks(XACT_EVENT_PARALLEL_ABORT);
else
CallXactCallbacks(XACT_EVENT_ABORT);
CallXactCallbacksOnce(XACT_EVENT_ABORT);
ResourceOwnerRelease(TopTransactionResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
AtEOXact_ComboCid_Dsm_Detach();
AtEOXact_Buffers(false);
AtEOXact_RelationCache(false);
AtEOXact_Inval(false);
AtEOXact_MultiXact();
ResourceOwnerRelease(TopTransactionResourceOwner,
RESOURCE_RELEASE_LOCKS,
false, true);
ResourceOwnerRelease(TopTransactionResourceOwner,
RESOURCE_RELEASE_AFTER_LOCKS,
false, true);
smgrDoPendingDeletes(false);
DoPendingDbDeletes(false);
DatabaseStorageResetSessionLock();
AtAbort_TablespaceStorage();
gp_guc_need_restore = true;
AtEOXact_GUC(false, 1);
gp_guc_need_restore = false;
AtEOXact_SPI(false);
AtEOXact_Enum();
AtEOXact_on_commit_actions(false);
AtEOXact_Namespace(false, is_parallel_worker);
AtEOXact_SMgr();
AtEOXact_Files(false);
AtEOXact_ComboCid();
AtEOXact_HashTables(false);
AtEOXact_PgStat(false, is_parallel_worker);
AtEOXact_ApplyLauncher(false);
AtEOXact_WorkFile();
pgstat_report_xact_timestamp(0);
}
/*
* Exported snapshots must be cleared before transaction ID is reset. In
* GPDB, transaction ID is reset below. In PostgreSQL, because 2PC is not
* needed, exported snapshots are cleared and transaction ID is reset
* later in CleanupTransaction(). We must perform both the actions here.
*/
AtEOXact_Snapshot(false, true); /* and release the transaction's snapshots */
/*
* If something goes wrong after this, we might recurse back to
* AbortTransaction(). To avoid creating another Abort WAL record
* and failing assertion in ProcArrayEndTransaction because MyProc->xid
* has already been cleared, clear out transactionId now. The rest
* of the fields in TransactionState will be cleared later, in
* CleanupTransaction().
*/
TopTransactionStateData.fullTransactionId = InvalidFullTransactionId;
MyProc->localDistribXactData.state = LOCALDISTRIBXACT_STATE_NONE;
/*
* State remains TRANS_ABORT until CleanupTransaction().
*/
RESUME_INTERRUPTS();
/* If a query was cancelled, then cleanup reader gangs. */
if (QueryCancelCleanup)
{
QueryCancelCleanup = false;
cdbcomponent_cleanupIdleQEs(false);
}
/*
* If memprot decides to kill process, make sure we destroy all processes
* so that all mem/resource will be freed
*/
if (elog_geterrcode() == ERRCODE_GP_MEMPROT_KILL)
DisconnectAndDestroyAllGangs(true);
/* Release resource group slot at the end of a transaction */
if (ShouldUnassignResGroup())
UnassignResGroup(false);
}
/*
* CleanupTransaction
*/
static void
CleanupTransaction(void)
{
TransactionState s = CurrentTransactionState;
/*
* State should still be TRANS_ABORT from AbortTransaction().
*/
if (s->state != TRANS_ABORT)
elog(FATAL, "CleanupTransaction: unexpected state %s",
TransStateAsString(s->state));
/*
* do abort cleanup processing
*/
AtCleanup_Portals(); /* now safe to release portal memory */
AtEOXact_Snapshot(false, true); /* and release the transaction's snapshots */
CurrentResourceOwner = NULL; /* and resource owner */
if (TopTransactionResourceOwner)
ResourceOwnerDelete(TopTransactionResourceOwner);
s->curTransactionOwner = NULL;
CurTransactionResourceOwner = NULL;
TopTransactionResourceOwner = NULL;
AtCleanup_Memory(); /* and transaction memory */
s->fullTransactionId = InvalidFullTransactionId;
s->subTransactionId = InvalidSubTransactionId;
s->nestingLevel = 0;
s->gucNestLevel = 0;
s->childXids = NULL;
s->nChildXids = 0;
s->maxChildXids = 0;
s->parallelModeLevel = 0;
s->executorSaysXactDoesWrites = false;
XactTopFullTransactionId = InvalidFullTransactionId;
nParallelCurrentXids = 0;
/*
* done with abort processing, set current transaction state back to
* default
*/
s->state = TRANS_DEFAULT;
finishDistributedTransactionContext("CleanupTransaction", true);
/* Release resource group slot at the end of a transaction */
if (ShouldUnassignResGroup())
UnassignResGroup(false);
}
/*
* StartTransactionCommand
*/
void
StartTransactionCommand(void)
{
if (Gp_role == GP_ROLE_DISPATCH)
setupRegularDtxContext();
TransactionState s = CurrentTransactionState;
switch (s->blockState)
{
/*
* if we aren't in a transaction block, we just do our usual start
* transaction.
*/
case TBLOCK_DEFAULT:
StartTransaction();
if (DistributedTransactionContext == DTX_CONTEXT_QE_TWO_PHASE_IMPLICIT_WRITER)
{
/*
* Pretend we executed an explicit BEGIN.
*/
s->blockState = TBLOCK_INPROGRESS;
}
else
{
/*
* Normal case.
*/
s->blockState = TBLOCK_STARTED;
}
break;
/*
* We are somewhere in a transaction block or subtransaction and
* about to start a new command. For now we do nothing, but
* someday we may do command-local resource initialization. (Note
* that any needed CommandCounterIncrement was done by the
* previous CommitTransactionCommand.)
*/
case TBLOCK_INPROGRESS:
case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_SUBINPROGRESS:
/*
* There may be reader gangs waiting for us to update the
* QDSentXID -- make sure the state of the sharedsnapshot
* slot properly tracks the qd-xid
*/
if (Gp_role == GP_ROLE_EXECUTE && Gp_is_writer && SharedLocalSnapshotSlot != NULL)
{
LWLockAcquire(SharedLocalSnapshotSlot->slotLock, LW_EXCLUSIVE);
FullTransactionId oldFullXid = SharedLocalSnapshotSlot->fullXid;
TimestampTz oldStartTimestamp = SharedLocalSnapshotSlot->startTimestamp;
/*
* MPP-3228: For a subtransaction, the transactionId
* may not have been assigned, we can't change the
* shared copy to InvalidTransactionId (the unassigned
* value) since the reader may *need* it).
*/
if (FullTransactionIdIsValid(s->fullTransactionId))
{
SharedLocalSnapshotSlot->fullXid = s->fullTransactionId;
}
SharedLocalSnapshotSlot->startTimestamp = xactStartTimestamp;
SharedLocalSnapshotSlot->distributedXid = QEDtxContextInfo.distributedXid;
LWLockRelease(SharedLocalSnapshotSlot->slotLock);
ereportif(Debug_print_full_dtm, LOG,
(errmsg("qExec WRITER updating shared xid: " UINT64_FORMAT " -> " UINT64_FORMAT " "
"(StartTransactionCommand) timestamp: "
INT64_FORMAT " -> " INT64_FORMAT ")",
U64FromFullTransactionId(oldFullXid),
U64FromFullTransactionId(s->fullTransactionId),
oldStartTimestamp, xactStartTimestamp)));
}
break;
/*
* Here we are in a failed transaction block (one of the commands
* caused an abort) so we do nothing but remain in the abort
* state. Eventually we will get a ROLLBACK command which will
* get us out of this state. (It is up to other code to ensure
* that no commands other than ROLLBACK will be processed in these
* states.)
*/
case TBLOCK_ABORT:
case TBLOCK_SUBABORT:
break;
/* These cases are invalid. */
case TBLOCK_STARTED:
case TBLOCK_BEGIN:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBBEGIN:
case TBLOCK_END:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
case TBLOCK_PREPARE:
elog(ERROR, "StartTransactionCommand: unexpected state %s",
BlockStateAsString(s->blockState));
break;
}
/*
* We must switch to CurTransactionContext before returning. This is
* already done if we called StartTransaction, otherwise not.
*/
Assert(CurTransactionContext != NULL);
MemoryContextSwitchTo(CurTransactionContext);
}
/*
* Simple system for saving and restoring transaction characteristics
* (isolation level, read only, deferrable). We need this for transaction
* chaining, so that we can set the characteristics of the new transaction to
* be the same as the previous one. (We need something like this because the
* GUC system resets the characteristics at transaction end, so for example
* just skipping the reset in StartTransaction() won't work.)
*/
static int save_XactIsoLevel;
static bool save_XactReadOnly;
static bool save_XactDeferrable;
void
SaveTransactionCharacteristics(void)
{
save_XactIsoLevel = XactIsoLevel;
save_XactReadOnly = XactReadOnly;
save_XactDeferrable = XactDeferrable;
}
void
RestoreTransactionCharacteristics(void)
{
XactIsoLevel = save_XactIsoLevel;
XactReadOnly = save_XactReadOnly;
XactDeferrable = save_XactDeferrable;
}
/*
* CommitTransactionCommand
*/
void
CommitTransactionCommand(void)
{
TransactionState s = CurrentTransactionState;
if (Gp_role == GP_ROLE_EXECUTE && !Gp_is_writer)
elog(DEBUG1,"CommitTransactionCommand: called as segment Reader in state %s",
BlockStateAsString(s->blockState));
if (s->chain)
SaveTransactionCharacteristics();
switch (s->blockState)
{
/*
* These shouldn't happen. TBLOCK_DEFAULT means the previous
* StartTransactionCommand didn't set the STARTED state
* appropriately, while TBLOCK_PARALLEL_INPROGRESS should be ended
* by EndParallelWorkerTransaction(), not this function.
*/
case TBLOCK_DEFAULT:
case TBLOCK_PARALLEL_INPROGRESS:
elog(FATAL, "CommitTransactionCommand: unexpected state %s",
BlockStateAsString(s->blockState));
break;
/*
* If we aren't in a transaction block, just do our usual
* transaction commit, and return to the idle state.
*/
case TBLOCK_STARTED:
CommitTransaction();
s->blockState = TBLOCK_DEFAULT;
break;
/*
* We are completing a "BEGIN TRANSACTION" command, so we change
* to the "transaction block in progress" state and return. (We
* assume the BEGIN did nothing to the database, so we need no
* CommandCounterIncrement.)
*/
case TBLOCK_BEGIN:
s->blockState = TBLOCK_INPROGRESS;
break;
/*
* This is the case when we have finished executing a command
* someplace within a transaction block. We increment the command
* counter and return.
*/
case TBLOCK_INPROGRESS:
case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_SUBINPROGRESS:
CommandCounterIncrement();
break;
/*
* We are completing a "COMMIT" command. Do it and return to the
* idle state.
*/
case TBLOCK_END:
CommitTransaction();
s->blockState = TBLOCK_DEFAULT;
if (s->chain)
{
StartTransaction();
s->blockState = TBLOCK_INPROGRESS;
s->chain = false;
RestoreTransactionCharacteristics();
}
break;
/*
* Here we are in the middle of a transaction block but one of the
* commands caused an abort so we do nothing but remain in the
* abort state. Eventually we will get a ROLLBACK command.
*/
case TBLOCK_ABORT:
case TBLOCK_SUBABORT:
break;
/*
* Here we were in an aborted transaction block and we just got
* the ROLLBACK command from the user, so clean up the
* already-aborted transaction and return to the idle state.
*/
case TBLOCK_ABORT_END:
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
if (s->chain)
{
StartTransaction();
s->blockState = TBLOCK_INPROGRESS;
s->chain = false;
RestoreTransactionCharacteristics();
}
break;
/*
* Here we were in a perfectly good transaction block but the user
* told us to ROLLBACK anyway. We have to abort the transaction
* and then clean up.
*/
case TBLOCK_ABORT_PENDING:
AbortTransaction();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
if (s->chain)
{
StartTransaction();
s->blockState = TBLOCK_INPROGRESS;
s->chain = false;
RestoreTransactionCharacteristics();
}
break;
/*
* We are completing a "PREPARE TRANSACTION" command. Do it and
* return to the idle state.
*/
case TBLOCK_PREPARE:
PrepareTransaction();
s->blockState = TBLOCK_DEFAULT;
break;
/*
* We were just issued a SAVEPOINT inside a transaction block.
* Start a subtransaction. (DefineSavepoint already did
* PushTransaction, so as to have someplace to put the SUBBEGIN
* state.)
*/
case TBLOCK_SUBBEGIN:
StartSubTransaction();
s->blockState = TBLOCK_SUBINPROGRESS;
break;
/*
* We were issued a RELEASE command, so we end the current
* subtransaction and return to the parent transaction. The parent
* might be ended too, so repeat till we find an INPROGRESS
* transaction or subtransaction.
*/
case TBLOCK_SUBRELEASE:
do
{
CommitSubTransaction();
s = CurrentTransactionState; /* changed by pop */
} while (s->blockState == TBLOCK_SUBRELEASE);
Assert(s->blockState == TBLOCK_INPROGRESS ||
s->blockState == TBLOCK_SUBINPROGRESS);
break;
/*
* We were issued a COMMIT, so we end the current subtransaction
* hierarchy and perform final commit. We do this by rolling up
* any subtransactions into their parent, which leads to O(N^2)
* operations with respect to resource owners - this isn't that
* bad until we approach a thousands of savepoints but is
* necessary for correctness should after triggers create new
* resource owners.
*/
case TBLOCK_SUBCOMMIT:
do
{
CommitSubTransaction();
s = CurrentTransactionState; /* changed by pop */
} while (s->blockState == TBLOCK_SUBCOMMIT);
/* If we had a COMMIT command, finish off the main xact too */
if (s->blockState == TBLOCK_END)
{
Assert(s->parent == NULL);
CommitTransaction();
s->blockState = TBLOCK_DEFAULT;
}
else if (s->blockState == TBLOCK_PREPARE)
{
Assert(s->parent == NULL);
PrepareTransaction();
s->blockState = TBLOCK_DEFAULT;
}
else
elog(ERROR, "CommitTransactionCommand: unexpected state %s",
BlockStateAsString(s->blockState));
break;
/*
* The current already-failed subtransaction is ending due to a
* ROLLBACK or ROLLBACK TO command, so pop it and recursively
* examine the parent (which could be in any of several states).
*/
case TBLOCK_SUBABORT_END:
CleanupSubTransaction();
CommitTransactionCommand();
break;
/*
* As above, but it's not dead yet, so abort first.
*/
case TBLOCK_SUBABORT_PENDING:
AbortSubTransaction();
CleanupSubTransaction();
CommitTransactionCommand();
break;
/*
* The current subtransaction is the target of a ROLLBACK TO
* command. Abort and pop it, then start a new subtransaction
* with the same name.
*/
case TBLOCK_SUBRESTART:
{
char *name;
int savepointLevel;
/* save name and keep Cleanup from freeing it */
name = s->name;
s->name = NULL;
savepointLevel = s->savepointLevel;
AbortSubTransaction();
CleanupSubTransaction();
if (Gp_role == GP_ROLE_DISPATCH)
{
DispatchRollbackToSavepoint(name);
}
DefineSavepoint(name);
s = CurrentTransactionState; /* changed by push */
if (name)
{
pfree(name);
}
s->savepointLevel = savepointLevel;
/* This is the same as TBLOCK_SUBBEGIN case */
AssertState(s->blockState == TBLOCK_SUBBEGIN);
StartSubTransaction();
s->blockState = TBLOCK_SUBINPROGRESS;
}
break;
/*
* Same as above, but the subtransaction had already failed, so we
* don't need AbortSubTransaction.
*/
case TBLOCK_SUBABORT_RESTART:
{
char *name;
int savepointLevel;
/* save name and keep Cleanup from freeing it */
name = s->name;
s->name = NULL;
savepointLevel = s->savepointLevel;
CleanupSubTransaction();
if (Gp_role == GP_ROLE_DISPATCH)
{
DispatchRollbackToSavepoint(name);
}
DefineSavepoint(name);
s = CurrentTransactionState; /* changed by push */
s->name = name;
s->savepointLevel = savepointLevel;
/* This is the same as TBLOCK_SUBBEGIN case */
AssertState(s->blockState == TBLOCK_SUBBEGIN);
StartSubTransaction();
s->blockState = TBLOCK_SUBINPROGRESS;
}
break;
}
}
/*
* AbortCurrentTransaction
*/
void
AbortCurrentTransaction(void)
{
TransactionState s = CurrentTransactionState;
elog(DEBUG5, "AbortCurrentTransaction for " UINT64_FORMAT " in state: %d",
U64FromFullTransactionId(s->fullTransactionId),
s->blockState);
switch (s->blockState)
{
case TBLOCK_DEFAULT:
if (s->state == TRANS_DEFAULT)
{
/* we are idle, so nothing to do */
}
else
{
/*
* We can get here after an error during transaction start
* (state will be TRANS_START). Need to clean up the
* incompletely started transaction. First, adjust the
* low-level state to suppress warning message from
* AbortTransaction.
*/
if (s->state == TRANS_START)
s->state = TRANS_INPROGRESS;
AbortTransaction();
CleanupTransaction();
}
break;
/*
* If we aren't in a transaction block, we just do the basic abort
* & cleanup transaction. For this purpose, we treat an implicit
* transaction block as if it were a simple statement.
*/
case TBLOCK_STARTED:
case TBLOCK_IMPLICIT_INPROGRESS:
AbortTransaction();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
break;
/*
* If we are in TBLOCK_BEGIN it means something screwed up right
* after reading "BEGIN TRANSACTION". We assume that the user
* will interpret the error as meaning the BEGIN failed to get him
* into a transaction block, so we should abort and return to idle
* state.
*/
case TBLOCK_BEGIN:
AbortTransaction();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
break;
/*
* We are somewhere in a transaction block and we've gotten a
* failure, so we abort the transaction and set up the persistent
* ABORT state. We will stay in ABORT until we get a ROLLBACK.
*/
case TBLOCK_INPROGRESS:
case TBLOCK_PARALLEL_INPROGRESS:
AbortTransaction();
s->blockState = TBLOCK_ABORT;
/* CleanupTransaction happens when we exit TBLOCK_ABORT_END */
break;
/*
* Here, we failed while trying to COMMIT. Clean up the
* transaction and return to idle state (we do not want to stay in
* the transaction).
*/
case TBLOCK_END:
AbortTransaction();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
break;
/*
* Here, we are already in an aborted transaction state and are
* waiting for a ROLLBACK, but for some reason we failed again! So
* we just remain in the abort state.
*/
case TBLOCK_ABORT:
case TBLOCK_SUBABORT:
break;
/*
* We are in a failed transaction and we got the ROLLBACK command.
* We have already aborted, we just need to cleanup and go to idle
* state.
*/
case TBLOCK_ABORT_END:
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
Assert(DistributedTransactionContext == DTX_CONTEXT_LOCAL_ONLY);
break;
/*
* We are in a live transaction and we got a ROLLBACK command.
* Abort, cleanup, go to idle state.
*/
case TBLOCK_ABORT_PENDING:
AbortTransaction();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
Assert(DistributedTransactionContext == DTX_CONTEXT_LOCAL_ONLY);
break;
/*
* Here, we failed while trying to PREPARE. Clean up the
* transaction and return to idle state (we do not want to stay in
* the transaction).
*/
case TBLOCK_PREPARE:
AbortTransaction();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
Assert(DistributedTransactionContext == DTX_CONTEXT_LOCAL_ONLY);
break;
/*
* We got an error inside a subtransaction. Abort just the
* subtransaction, and go to the persistent SUBABORT state until
* we get ROLLBACK.
*/
case TBLOCK_SUBINPROGRESS:
AbortSubTransaction();
s->blockState = TBLOCK_SUBABORT;
break;
/*
* If we failed while trying to create a subtransaction, clean up
* the broken subtransaction and abort the parent. The same
* applies if we get a failure while ending a subtransaction.
*/
case TBLOCK_SUBBEGIN:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
AbortSubTransaction();
CleanupSubTransaction();
AbortCurrentTransaction();
break;
/*
* Same as above, except the Abort() was already done.
*/
case TBLOCK_SUBABORT_END:
case TBLOCK_SUBABORT_RESTART:
CleanupSubTransaction();
AbortCurrentTransaction();
break;
}
}
/*
* PreventInTransactionBlock
*
* This routine is to be called by statements that must not run inside
* a transaction block, typically because they have non-rollback-able
* side effects or do internal commits.
*
* If we have already started a transaction block, issue an error; also issue
* an error if we appear to be running inside a user-defined function (which
* could issue more commands and possibly cause a failure after the statement
* completes). Subtransactions are verboten too.
*
* isTopLevel: passed down from ProcessUtility to determine whether we are
* inside a function. (We will always fail if this is false, but it's
* convenient to centralize the check here instead of making callers do it.)
* stmtType: statement type name, for error messages.
*/
void
PreventInTransactionBlock(bool isTopLevel, const char *stmtType)
{
/*
* xact block already started?
*/
if (IsTransactionBlock())
ereport(ERROR,
(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s cannot run inside a transaction block",
stmtType)));
/*
* subtransaction?
*/
if (IsSubTransaction())
ereport(ERROR,
(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s cannot run inside a subtransaction",
stmtType)));
/*
* inside a function call?
*/
if (!isTopLevel)
ereport(ERROR,
(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s cannot be executed from a function", stmtType)));
/* If we got past IsTransactionBlock test, should be in default state */
if (CurrentTransactionState->blockState != TBLOCK_DEFAULT &&
CurrentTransactionState->blockState != TBLOCK_STARTED)
elog(FATAL, "cannot prevent transaction chain");
/* all okay */
}
/*
* WarnNoTransactionBlock
* RequireTransactionBlock
*
* These two functions allow for warnings or errors if a command is executed
* outside of a transaction block. This is useful for commands that have no
* effects that persist past transaction end (and so calling them outside a
* transaction block is presumably an error). DECLARE CURSOR is an example.
* While top-level transaction control commands (BEGIN/COMMIT/ABORT) and SET
* that have no effect issue warnings, all other no-effect commands generate
* errors.
*
* If we appear to be running inside a user-defined function, we do not
* issue anything, since the function could issue more commands that make
* use of the current statement's results. Likewise subtransactions.
* Thus these are inverses for PreventInTransactionBlock.
*
* isTopLevel: passed down from ProcessUtility to determine whether we are
* inside a function.
* stmtType: statement type name, for warning or error messages.
*/
void
WarnNoTransactionBlock(bool isTopLevel, const char *stmtType)
{
CheckTransactionBlock(isTopLevel, false, stmtType);
}
void
RequireTransactionBlock(bool isTopLevel, const char *stmtType)
{
CheckTransactionBlock(isTopLevel, true, stmtType);
}
/*
* This is the implementation of the above two.
*/
static void
CheckTransactionBlock(bool isTopLevel, bool throwError, const char *stmtType)
{
/*
* xact block already started?
*/
if (IsTransactionBlock())
return;
/*
* subtransaction?
*/
if (IsSubTransaction())
return;
/*
* inside a function call?
*/
if (!isTopLevel)
return;
ereport(throwError ? ERROR : WARNING,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s can only be used in transaction blocks",
stmtType)));
return;
}
/*
* IsInTransactionBlock
*
* This routine is for statements that need to behave differently inside
* a transaction block than when running as single commands. ANALYZE is
* currently the only example.
*
* isTopLevel: passed down from ProcessUtility to determine whether we are
* inside a function.
*/
bool
IsInTransactionBlock(bool isTopLevel)
{
/*
* Return true on same conditions that would make
* PreventInTransactionBlock error out
*/
if (IsTransactionBlock())
return true;
if (IsSubTransaction())
return true;
if (!isTopLevel)
return true;
if (CurrentTransactionState->blockState != TBLOCK_DEFAULT &&
CurrentTransactionState->blockState != TBLOCK_STARTED)
return true;
return false;
}
/*
* Register or deregister callback functions for start- and end-of-xact
* operations.
*
* These functions are intended for use by dynamically loaded modules.
* For built-in modules we generally just hardwire the appropriate calls
* (mainly because it's easier to control the order that way, where needed).
*
* At transaction end, the callback occurs post-commit or post-abort, so the
* callback functions can only do noncritical cleanup.
*/
void
RegisterXactCallback(XactCallback callback, void *arg)
{
XactCallbackItem *item;
item = (XactCallbackItem *)
MemoryContextAlloc(TopMemoryContext, sizeof(XactCallbackItem));
item->callback = callback;
item->arg = arg;
item->next = Xact_callbacks;
Xact_callbacks = item;
}
void
UnregisterXactCallback(XactCallback callback, void *arg)
{
XactCallbackItem *item;
XactCallbackItem *prev;
prev = NULL;
for (item = Xact_callbacks; item; prev = item, item = item->next)
{
if (item->callback == callback && item->arg == arg)
{
if (prev)
prev->next = item->next;
else
Xact_callbacks = item->next;
pfree(item);
break;
}
}
}
static void
CallXactCallbacks(XactEvent event)
{
XactCallbackItem *item;
for (item = Xact_callbacks; item; item = item->next)
item->callback(event, item->arg);
}
/* Register or deregister callback functions for start/end Xact. Call only once. */
void
RegisterXactCallbackOnce(XactCallback callback, void *arg)
{
XactCallbackItem *item;
item = (XactCallbackItem *)
MemoryContextAlloc(TopMemoryContext, sizeof(XactCallbackItem));
item->callback = callback;
item->arg = arg;
item->next = Xact_callbacks_once;
Xact_callbacks_once = item;
}
void
UnregisterXactCallbackOnce(XactCallback callback, void *arg)
{
XactCallbackItem *item;
XactCallbackItem *prev;
prev = NULL;
for (item = Xact_callbacks_once; item; prev = item, item = item->next)
{
if (item->callback == callback && item->arg == arg)
{
if (prev)
prev->next = item->next;
else
Xact_callbacks_once = item->next;
pfree(item);
break;
}
}
}
static void
CallXactCallbacksOnce(XactEvent event)
{
/* currently callback once should ignore prepare. */
if (event == XACT_EVENT_PREPARE)
return;
while(Xact_callbacks_once)
{
XactCallbackItem *next = Xact_callbacks_once->next;
XactCallback callback=Xact_callbacks_once->callback;
void*arg=Xact_callbacks_once->arg;
pfree(Xact_callbacks_once);
Xact_callbacks_once = next;
callback(event,arg);
}
}
/*
* Register or deregister callback functions for start- and end-of-subxact
* operations.
*
* Pretty much same as above, but for subtransaction events.
*
* At subtransaction end, the callback occurs post-subcommit or post-subabort,
* so the callback functions can only do noncritical cleanup. At
* subtransaction start, the callback is called when the subtransaction has
* finished initializing.
*/
void
RegisterSubXactCallback(SubXactCallback callback, void *arg)
{
SubXactCallbackItem *item;
item = (SubXactCallbackItem *)
MemoryContextAlloc(TopMemoryContext, sizeof(SubXactCallbackItem));
item->callback = callback;
item->arg = arg;
item->next = SubXact_callbacks;
SubXact_callbacks = item;
}
void
UnregisterSubXactCallback(SubXactCallback callback, void *arg)
{
SubXactCallbackItem *item;
SubXactCallbackItem *prev;
prev = NULL;
for (item = SubXact_callbacks; item; prev = item, item = item->next)
{
if (item->callback == callback && item->arg == arg)
{
if (prev)
prev->next = item->next;
else
SubXact_callbacks = item->next;
pfree(item);
break;
}
}
}
static void
CallSubXactCallbacks(SubXactEvent event,
SubTransactionId mySubid,
SubTransactionId parentSubid)
{
SubXactCallbackItem *item;
for (item = SubXact_callbacks; item; item = item->next)
item->callback(event, mySubid, parentSubid, item->arg);
}
/* ----------------------------------------------------------------
* transaction block support
* ----------------------------------------------------------------
*/
/*
* BeginTransactionBlock
* This executes a BEGIN command.
*/
void
BeginTransactionBlock(void)
{
TransactionState s = CurrentTransactionState;
switch (s->blockState)
{
/*
* We are not inside a transaction block, so allow one to begin.
*/
case TBLOCK_STARTED:
s->blockState = TBLOCK_BEGIN;
break;
/*
* BEGIN converts an implicit transaction block to a regular one.
* (Note that we allow this even if we've already done some
* commands, which is a bit odd but matches historical practice.)
*/
case TBLOCK_IMPLICIT_INPROGRESS:
s->blockState = TBLOCK_BEGIN;
break;
/*
* Already a transaction block in progress.
*/
case TBLOCK_INPROGRESS:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBINPROGRESS:
case TBLOCK_ABORT:
case TBLOCK_SUBABORT:
ereport(Gp_role == GP_ROLE_EXECUTE ? DEBUG1 : WARNING,
(errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
errmsg("there is already a transaction in progress")));
break;
/* These cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_BEGIN:
case TBLOCK_SUBBEGIN:
case TBLOCK_END:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
case TBLOCK_PREPARE:
elog(FATAL, "BeginTransactionBlock: unexpected state %s",
BlockStateAsString(s->blockState));
break;
}
}
/*
* PrepareTransactionBlock
* This executes a PREPARE command.
*
* Since PREPARE may actually do a ROLLBACK, the result indicates what
* happened: true for PREPARE, false for ROLLBACK.
*
* Note that we don't actually do anything here except change blockState.
* The real work will be done in the upcoming PrepareTransaction().
* We do it this way because it's not convenient to change memory context,
* resource owner, etc while executing inside a Portal.
*/
bool
PrepareTransactionBlock(const char *gid)
{
TransactionState s;
bool result;
/* Set up to commit the current transaction */
result = EndTransactionBlock(false);
/* If successful, change outer tblock state to PREPARE */
if (result)
{
s = CurrentTransactionState;
while (s->parent != NULL)
s = s->parent;
if (s->blockState == TBLOCK_END)
{
/* Save GID where PrepareTransaction can find it again */
prepareGID = MemoryContextStrdup(TopTransactionContext, gid);
s->blockState = TBLOCK_PREPARE;
}
else
{
/*
* ignore case where we are not in a transaction;
* EndTransactionBlock already issued a warning.
*/
Assert(s->blockState == TBLOCK_STARTED ||
s->blockState == TBLOCK_IMPLICIT_INPROGRESS);
/* Don't send back a PREPARE result tag... */
result = false;
}
}
return result;
}
/*
* EndTransactionBlock
* This executes a COMMIT command.
*
* Since COMMIT may actually do a ROLLBACK, the result indicates what
* happened: true for COMMIT, false for ROLLBACK.
*
* Note that we don't actually do anything here except change blockState.
* The real work will be done in the upcoming CommitTransactionCommand().
* We do it this way because it's not convenient to change memory context,
* resource owner, etc while executing inside a Portal.
*/
bool
EndTransactionBlock(bool chain)
{
TransactionState s = CurrentTransactionState;
bool result = false;
switch (s->blockState)
{
/*
* We are in a transaction block, so tell CommitTransactionCommand
* to COMMIT.
*/
case TBLOCK_INPROGRESS:
s->blockState = TBLOCK_END;
result = true;
break;
/*
* We are in an implicit transaction block. If AND CHAIN was
* specified, error. Otherwise commit, but issue a warning
* because there was no explicit BEGIN before this.
*/
case TBLOCK_IMPLICIT_INPROGRESS:
if (chain)
ereport(ERROR,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s can only be used in transaction blocks",
"COMMIT AND CHAIN")));
else
ereport(WARNING,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
errmsg("there is no transaction in progress")));
s->blockState = TBLOCK_END;
result = true;
break;
/*
* We are in a failed transaction block. Tell
* CommitTransactionCommand it's time to exit the block.
*/
case TBLOCK_ABORT:
s->blockState = TBLOCK_ABORT_END;
break;
/*
* We are in a live subtransaction block. Set up to subcommit all
* open subtransactions and then commit the main transaction.
*/
case TBLOCK_SUBINPROGRESS:
while (s->parent != NULL)
{
if (s->blockState == TBLOCK_SUBINPROGRESS)
s->blockState = TBLOCK_SUBCOMMIT;
else
elog(FATAL, "EndTransactionBlock: unexpected state %s",
BlockStateAsString(s->blockState));
s = s->parent;
}
if (s->blockState == TBLOCK_INPROGRESS)
s->blockState = TBLOCK_END;
else
elog(FATAL, "EndTransactionBlock: unexpected state %s",
BlockStateAsString(s->blockState));
result = true;
break;
/*
* Here we are inside an aborted subtransaction. Treat the COMMIT
* as ROLLBACK: set up to abort everything and exit the main
* transaction.
*/
case TBLOCK_SUBABORT:
while (s->parent != NULL)
{
if (s->blockState == TBLOCK_SUBINPROGRESS)
s->blockState = TBLOCK_SUBABORT_PENDING;
else if (s->blockState == TBLOCK_SUBABORT)
s->blockState = TBLOCK_SUBABORT_END;
else
elog(FATAL, "EndTransactionBlock: unexpected state %s",
BlockStateAsString(s->blockState));
s = s->parent;
}
if (s->blockState == TBLOCK_INPROGRESS)
s->blockState = TBLOCK_ABORT_PENDING;
else if (s->blockState == TBLOCK_ABORT)
s->blockState = TBLOCK_ABORT_END;
else
elog(FATAL, "EndTransactionBlock: unexpected state %s",
BlockStateAsString(s->blockState));
break;
/*
* The user issued COMMIT when not inside a transaction. For
* COMMIT without CHAIN, issue a WARNING, staying in
* TBLOCK_STARTED state. The upcoming call to
* CommitTransactionCommand() will then close the transaction and
* put us back into the default state. For COMMIT AND CHAIN,
* error.
*/
case TBLOCK_STARTED:
if (chain)
ereport(ERROR,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s can only be used in transaction blocks",
"COMMIT AND CHAIN")));
else
ereport((Gp_role == GP_ROLE_EXECUTE) ? DEBUG2 : WARNING,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
errmsg("there is no transaction in progress")));
result = true;
break;
/*
* The user issued a COMMIT that somehow ran inside a parallel
* worker. We can't cope with that.
*/
case TBLOCK_PARALLEL_INPROGRESS:
ereport(FATAL,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot commit during a parallel operation")));
break;
/* These cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_BEGIN:
case TBLOCK_SUBBEGIN:
case TBLOCK_END:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
case TBLOCK_PREPARE:
elog(FATAL, "EndTransactionBlock: unexpected state %s",
BlockStateAsString(s->blockState));
break;
}
Assert(s->blockState == TBLOCK_STARTED ||
s->blockState == TBLOCK_END ||
s->blockState == TBLOCK_ABORT_END ||
s->blockState == TBLOCK_ABORT_PENDING);
s->chain = chain;
return result;
}
/*
* UserAbortTransactionBlock
* This executes a ROLLBACK command.
*
* As above, we don't actually do anything here except change blockState.
*/
void
UserAbortTransactionBlock(bool chain)
{
TransactionState s = CurrentTransactionState;
switch (s->blockState)
{
/*
* We are inside a transaction block and we got a ROLLBACK command
* from the user, so tell CommitTransactionCommand to abort and
* exit the transaction block.
*/
case TBLOCK_INPROGRESS:
s->blockState = TBLOCK_ABORT_PENDING;
break;
/*
* We are inside a failed transaction block and we got a ROLLBACK
* command from the user. Abort processing is already done, so
* CommitTransactionCommand just has to cleanup and go back to
* idle state.
*/
case TBLOCK_ABORT:
s->blockState = TBLOCK_ABORT_END;
break;
/*
* We are inside a subtransaction. Mark everything up to top
* level as exitable.
*/
case TBLOCK_SUBINPROGRESS:
case TBLOCK_SUBABORT:
while (s->parent != NULL)
{
if (s->blockState == TBLOCK_SUBINPROGRESS)
s->blockState = TBLOCK_SUBABORT_PENDING;
else if (s->blockState == TBLOCK_SUBABORT)
s->blockState = TBLOCK_SUBABORT_END;
else
elog(FATAL, "UserAbortTransactionBlock: unexpected state %s",
BlockStateAsString(s->blockState));
s = s->parent;
}
if (s->blockState == TBLOCK_INPROGRESS)
s->blockState = TBLOCK_ABORT_PENDING;
else if (s->blockState == TBLOCK_ABORT)
s->blockState = TBLOCK_ABORT_END;
else
elog(FATAL, "UserAbortTransactionBlock: unexpected state %s",
BlockStateAsString(s->blockState));
break;
/*
* The user issued ABORT when not inside a transaction. For
* ROLLBACK without CHAIN, issue a WARNING and go to abort state.
* The upcoming call to CommitTransactionCommand() will then put
* us back into the default state. For ROLLBACK AND CHAIN, error.
*
* We do the same thing with ABORT inside an implicit transaction,
* although in this case we might be rolling back actual database
* state changes. (It's debatable whether we should issue a
* WARNING in this case, but we have done so historically.)
*/
case TBLOCK_STARTED:
case TBLOCK_IMPLICIT_INPROGRESS:
if (chain)
ereport(ERROR,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s can only be used in transaction blocks",
"ROLLBACK AND CHAIN")));
else
ereport((Gp_role == GP_ROLE_EXECUTE) ? DEBUG2 : WARNING,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
errmsg("there is no transaction in progress")));
s->blockState = TBLOCK_ABORT_PENDING;
break;
/*
* The user issued an ABORT that somehow ran inside a parallel
* worker. We can't cope with that.
*/
case TBLOCK_PARALLEL_INPROGRESS:
ereport(FATAL,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot abort during a parallel operation")));
break;
/* These cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_BEGIN:
case TBLOCK_SUBBEGIN:
case TBLOCK_END:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
case TBLOCK_PREPARE:
elog(FATAL, "UserAbortTransactionBlock: unexpected state %s",
BlockStateAsString(s->blockState));
break;
}
Assert(s->blockState == TBLOCK_ABORT_END ||
s->blockState == TBLOCK_ABORT_PENDING);
s->chain = chain;
}
/*
* BeginImplicitTransactionBlock
* Start an implicit transaction block if we're not already in one.
*
* Unlike BeginTransactionBlock, this is called directly from the main loop
* in postgres.c, not within a Portal. So we can just change blockState
* without a lot of ceremony. We do not expect caller to do
* CommitTransactionCommand/StartTransactionCommand.
*/
void
BeginImplicitTransactionBlock(void)
{
TransactionState s = CurrentTransactionState;
/*
* If we are in STARTED state (that is, no transaction block is open),
* switch to IMPLICIT_INPROGRESS state, creating an implicit transaction
* block.
*
* For caller convenience, we consider all other transaction states as
* legal here; otherwise the caller would need its own state check, which
* seems rather pointless.
*/
if (s->blockState == TBLOCK_STARTED)
s->blockState = TBLOCK_IMPLICIT_INPROGRESS;
}
/*
* EndImplicitTransactionBlock
* End an implicit transaction block, if we're in one.
*
* Like EndTransactionBlock, we just make any needed blockState change here.
* The real work will be done in the upcoming CommitTransactionCommand().
*/
void
EndImplicitTransactionBlock(void)
{
TransactionState s = CurrentTransactionState;
/*
* If we are in IMPLICIT_INPROGRESS state, switch back to STARTED state,
* allowing CommitTransactionCommand to commit whatever happened during
* the implicit transaction block as though it were a single statement.
*
* For caller convenience, we consider all other transaction states as
* legal here; otherwise the caller would need its own state check, which
* seems rather pointless.
*/
if (s->blockState == TBLOCK_IMPLICIT_INPROGRESS)
s->blockState = TBLOCK_STARTED;
}
void
DefineDispatchSavepoint(char *name)
{
TransactionState s = CurrentTransactionState;
if ((s->blockState != TBLOCK_INPROGRESS) &&
(s->blockState != TBLOCK_SUBINPROGRESS))
{
elog(FATAL, "DefineSavepoint: unexpected state %s",
BlockStateAsString(s->blockState));
}
/* First we attempt to create on the QEs */
if (Gp_role == GP_ROLE_DISPATCH)
{
char *cmd;
cmd = psprintf("SAVEPOINT %s", quote_identifier(name));
/*
* dispatch a DTX command, in the event of an error, this call
* will either exit via elog()/ereport() or return false
*/
if (!dispatchDtxCommand(cmd))
elog(ERROR, "Could not create a new savepoint (%s)", cmd);
pfree(cmd);
}
DefineSavepoint(name);
}
/*
* DefineSavepoint
* This executes a SAVEPOINT command.
*/
void
DefineSavepoint(const char *name)
{
TransactionState s = CurrentTransactionState;
/*
* Workers synchronize transaction state at the beginning of each parallel
* operation, so we can't account for new subtransactions after that
* point. (Note that this check will certainly error out if s->blockState
* is TBLOCK_PARALLEL_INPROGRESS, so we can treat that as an invalid case
* below.)
*/
if (IsInParallelMode())
ereport(ERROR,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot define savepoints during a parallel operation")));
switch (s->blockState)
{
case TBLOCK_INPROGRESS:
case TBLOCK_SUBINPROGRESS:
/* Normal subtransaction start */
PushTransaction();
s = CurrentTransactionState; /* changed by push */
/*
* Savepoint names, like the TransactionState block itself, live
* in TopTransactionContext.
*/
if (name)
s->name = MemoryContextStrdup(TopTransactionContext, name);
break;
/*
* We disallow savepoint commands in implicit transaction blocks.
* There would be no great difficulty in allowing them so far as
* this module is concerned, but a savepoint seems inconsistent
* with exec_simple_query's behavior of abandoning the whole query
* string upon error. Also, the point of an implicit transaction
* block (as opposed to a regular one) is to automatically close
* after an error, so it's hard to see how a savepoint would fit
* into that.
*
* The error messages for this are phrased as if there were no
* active transaction block at all, which is historical but
* perhaps could be improved.
*/
case TBLOCK_IMPLICIT_INPROGRESS:
ereport(ERROR,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s can only be used in transaction blocks",
"SAVEPOINT")));
break;
/* These cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_STARTED:
case TBLOCK_BEGIN:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBBEGIN:
case TBLOCK_END:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_ABORT:
case TBLOCK_SUBABORT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
case TBLOCK_PREPARE:
elog(FATAL, "DefineSavepoint: unexpected state %s",
BlockStateAsString(s->blockState));
break;
}
}
/*
* ReleaseSavepoint
* This executes a RELEASE command.
*
* As above, we don't actually do anything here except change blockState.
*/
void
ReleaseSavepoint(const char *name)
{
TransactionState s = CurrentTransactionState;
TransactionState target,
xact;
/*
* Workers synchronize transaction state at the beginning of each parallel
* operation, so we can't account for transaction state change after that
* point. (Note that this check will certainly error out if s->blockState
* is TBLOCK_PARALLEL_INPROGRESS, so we can treat that as an invalid case
* below.)
*/
if (IsInParallelMode())
ereport(ERROR,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot release savepoints during a parallel operation")));
switch (s->blockState)
{
/*
* We can't release a savepoint if there is no savepoint defined.
*/
case TBLOCK_INPROGRESS:
ereport(ERROR,
(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
errmsg("savepoint \"%s\" does not exist", name)));
break;
case TBLOCK_IMPLICIT_INPROGRESS:
/* See comment about implicit transactions in DefineSavepoint */
ereport(ERROR,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s can only be used in transaction blocks",
"RELEASE SAVEPOINT")));
break;
/*
* We are in a non-aborted subtransaction. This is the only valid
* case.
*/
case TBLOCK_SUBINPROGRESS:
break;
/* These cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_STARTED:
case TBLOCK_BEGIN:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBBEGIN:
case TBLOCK_END:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_ABORT:
case TBLOCK_SUBABORT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
case TBLOCK_PREPARE:
elog(FATAL, "ReleaseSavepoint: unexpected state %s",
BlockStateAsString(s->blockState));
break;
}
if (Gp_role == GP_ROLE_DISPATCH)
{
char *cmd;
cmd = psprintf("RELEASE SAVEPOINT %s", quote_identifier(name));
/*
* dispatch a DTX command, in the event of an error, this call will
* either exit via elog()/ereport() or return false
*/
if (!dispatchDtxCommand(cmd))
elog(ERROR, "Could not release savepoint (%s)", cmd);
pfree(cmd);
}
for (target = s; PointerIsValid(target); target = target->parent)
{
if (PointerIsValid(target->name) && strcmp(target->name, name) == 0)
break;
}
if (!PointerIsValid(target))
ereport(ERROR,
(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
errmsg("savepoint \"%s\" does not exist", name)));
/* disallow crossing savepoint level boundaries */
if (target->savepointLevel != s->savepointLevel)
ereport(ERROR,
(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
errmsg("savepoint \"%s\" does not exist within current savepoint level", name)));
/*
* Mark "commit pending" all subtransactions up to the target
* subtransaction. The actual commits will happen when control gets to
* CommitTransactionCommand.
*/
xact = CurrentTransactionState;
for (;;)
{
Assert(xact->blockState == TBLOCK_SUBINPROGRESS);
xact->blockState = TBLOCK_SUBRELEASE;
if (xact == target)
break;
xact = xact->parent;
Assert(PointerIsValid(xact));
}
}
/*
* RollbackToSavepoint
* This executes a ROLLBACK TO <savepoint> command.
*
* As above, we don't actually do anything here except change blockState.
*/
void
RollbackToSavepoint(const char *name)
{
TransactionState s = CurrentTransactionState;
TransactionState target,
xact;
/*
* Workers synchronize transaction state at the beginning of each parallel
* operation, so we can't account for transaction state change after that
* point. (Note that this check will certainly error out if s->blockState
* is TBLOCK_PARALLEL_INPROGRESS, so we can treat that as an invalid case
* below.)
*/
if (IsInParallelMode())
ereport(ERROR,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot rollback to savepoints during a parallel operation")));
switch (s->blockState)
{
/*
* We can't rollback to a savepoint if there is no savepoint
* defined.
*/
case TBLOCK_INPROGRESS:
case TBLOCK_ABORT:
ereport(ERROR,
(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
errmsg("savepoint \"%s\" does not exist", name)));
break;
case TBLOCK_IMPLICIT_INPROGRESS:
/* See comment about implicit transactions in DefineSavepoint */
ereport(ERROR,
(errcode(ERRCODE_NO_ACTIVE_SQL_TRANSACTION),
/* translator: %s represents an SQL statement name */
errmsg("%s can only be used in transaction blocks",
"ROLLBACK TO SAVEPOINT")));
break;
/*
* There is at least one savepoint, so proceed.
*/
case TBLOCK_SUBINPROGRESS:
case TBLOCK_SUBABORT:
break;
/* These cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_STARTED:
case TBLOCK_BEGIN:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBBEGIN:
case TBLOCK_END:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
case TBLOCK_PREPARE:
elog(FATAL, "RollbackToSavepoint: unexpected state %s",
BlockStateAsString(s->blockState));
break;
}
for (target = s; PointerIsValid(target); target = target->parent)
{
if (PointerIsValid(target->name) && strcmp(target->name, name) == 0)
break;
}
if (!PointerIsValid(target))
ereport(ERROR,
(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
errmsg("savepoint \"%s\" does not exist", name)));
/* disallow crossing savepoint level boundaries */
if (target->savepointLevel != s->savepointLevel)
ereport(ERROR,
(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
errmsg("savepoint \"%s\" does not exist within current savepoint level", name)));
/*
* Mark "abort pending" all subtransactions up to the target
* subtransaction. The actual aborts will happen when control gets to
* CommitTransactionCommand.
*/
xact = CurrentTransactionState;
for (;;)
{
if (xact == target)
break;
if (xact->blockState == TBLOCK_SUBINPROGRESS)
xact->blockState = TBLOCK_SUBABORT_PENDING;
else if (xact->blockState == TBLOCK_SUBABORT)
xact->blockState = TBLOCK_SUBABORT_END;
else
elog(FATAL, "RollbackToSavepoint: unexpected state %s",
BlockStateAsString(xact->blockState));
xact = xact->parent;
Assert(PointerIsValid(xact));
}
/* And mark the target as "restart pending" */
if (xact->blockState == TBLOCK_SUBINPROGRESS)
xact->blockState = TBLOCK_SUBRESTART;
else if (xact->blockState == TBLOCK_SUBABORT)
xact->blockState = TBLOCK_SUBABORT_RESTART;
else
elog(FATAL, "RollbackToSavepoint: unexpected state %s",
BlockStateAsString(xact->blockState));
}
static void
DispatchRollbackToSavepoint(char *name)
{
char *cmd;
if (!name)
elog(ERROR, "could not find savepoint name for ROLLBACK TO SAVEPOINT");
cmd = psprintf("ROLLBACK TO SAVEPOINT %s", quote_identifier(name));
/*
* dispatch a DTX command, in the event of an error, this call will
* either exit via elog()/ereport() or return false
*/
if (!dispatchDtxCommand(cmd))
ereport(ERROR, (errcode(ERRCODE_GP_INTERCONNECTION_ERROR),
errmsg("Could not rollback to savepoint (%s)", cmd)));
pfree(cmd);
}
/*
* BeginInternalSubTransaction
* This is the same as DefineSavepoint except it allows TBLOCK_STARTED,
* TBLOCK_IMPLICIT_INPROGRESS, TBLOCK_END, and TBLOCK_PREPARE states,
* and therefore it can safely be used in functions that might be called
* when not inside a BEGIN block or when running deferred triggers at
* COMMIT/PREPARE time. Also, it automatically does
* CommitTransactionCommand/StartTransactionCommand instead of expecting
* the caller to do it.
*/
void
BeginInternalSubTransaction(const char *name)
{
TransactionState s = CurrentTransactionState;
if (Gp_role == GP_ROLE_DISPATCH)
{
if (!doDispatchSubtransactionInternalCmd(
DTX_PROTOCOL_COMMAND_SUBTRANSACTION_BEGIN_INTERNAL))
{
elog(ERROR,
"Could not BeginInternalSubTransaction dispatch failed");
}
}
/*
* Workers synchronize transaction state at the beginning of each parallel
* operation, so we can't account for new subtransactions after that
* point. We might be able to make an exception for the type of
* subtransaction established by this function, which is typically used in
* contexts where we're going to release or roll back the subtransaction
* before proceeding further, so that no enduring change to the
* transaction state occurs. For now, however, we prohibit this case along
* with all the others.
*/
if (IsInParallelMode())
ereport(ERROR,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot start subtransactions during a parallel operation")));
switch (s->blockState)
{
case TBLOCK_STARTED:
case TBLOCK_INPROGRESS:
case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_END:
case TBLOCK_PREPARE:
case TBLOCK_SUBINPROGRESS:
/* Normal subtransaction start */
PushTransaction();
s = CurrentTransactionState; /* changed by push */
/*
* Savepoint names, like the TransactionState block itself, live
* in TopTransactionContext.
*/
if (name)
s->name = MemoryContextStrdup(TopTransactionContext, name);
break;
/* These cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_BEGIN:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBBEGIN:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_ABORT:
case TBLOCK_SUBABORT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
elog(FATAL, "BeginInternalSubTransaction: unexpected state %s",
BlockStateAsString(s->blockState));
break;
}
CommitTransactionCommand();
StartTransactionCommand();
}
/*
* ReleaseCurrentSubTransaction
*
* RELEASE (ie, commit) the innermost subtransaction, regardless of its
* savepoint name (if any).
* NB: do NOT use CommitTransactionCommand/StartTransactionCommand with this.
*/
void
ReleaseCurrentSubTransaction(void)
{
TransactionState s = CurrentTransactionState;
/*
* Workers synchronize transaction state at the beginning of each parallel
* operation, so we can't account for commit of subtransactions after that
* point. This should not happen anyway. Code calling this would
* typically have called BeginInternalSubTransaction() first, failing
* there.
*/
if (IsInParallelMode())
ereport(ERROR,
(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
errmsg("cannot commit subtransactions during a parallel operation")));
if (s->blockState != TBLOCK_SUBINPROGRESS)
elog(ERROR, "ReleaseCurrentSubTransaction: unexpected state %s",
BlockStateAsString(s->blockState));
Assert(s->state == TRANS_INPROGRESS);
if (Gp_role == GP_ROLE_DISPATCH)
{
if (!doDispatchSubtransactionInternalCmd(
DTX_PROTOCOL_COMMAND_SUBTRANSACTION_RELEASE_INTERNAL))
{
elog(ERROR,
"Could not ReleaseCurrentSubTransaction dispatch failed");
}
}
MemoryContextSwitchTo(CurTransactionContext);
CommitSubTransaction();
s = CurrentTransactionState; /* changed by pop */
Assert(s->state == TRANS_INPROGRESS);
}
/*
* RollbackAndReleaseCurrentSubTransaction
*
* ROLLBACK and RELEASE (ie, abort) the innermost subtransaction, regardless
* of its savepoint name (if any).
* NB: do NOT use CommitTransactionCommand/StartTransactionCommand with this.
*/
void
RollbackAndReleaseCurrentSubTransaction(void)
{
TransactionState s = CurrentTransactionState;
/*
* Unlike ReleaseCurrentSubTransaction(), this is nominally permitted
* during parallel operations. That's because we may be in the master,
* recovering from an error thrown while we were in parallel mode. We
* won't reach here in a worker, because BeginInternalSubTransaction()
* will have failed.
*/
switch (s->blockState)
{
/* Must be in a subtransaction */
case TBLOCK_SUBINPROGRESS:
case TBLOCK_SUBABORT:
break;
/* These cases are invalid. */
case TBLOCK_DEFAULT:
case TBLOCK_STARTED:
case TBLOCK_BEGIN:
case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBBEGIN:
case TBLOCK_INPROGRESS:
case TBLOCK_END:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_ABORT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
case TBLOCK_PREPARE:
elog(FATAL, "RollbackAndReleaseCurrentSubTransaction: unexpected state %s",
BlockStateAsString(s->blockState));
break;
}
/*
* Abort the current subtransaction, if needed.
*/
if (s->blockState == TBLOCK_SUBINPROGRESS)
AbortSubTransaction();
/* And clean it up, too */
CleanupSubTransaction();
s = CurrentTransactionState; /* changed by pop */
AssertState(s->blockState == TBLOCK_SUBINPROGRESS ||
s->blockState == TBLOCK_INPROGRESS ||
s->blockState == TBLOCK_IMPLICIT_INPROGRESS ||
s->blockState == TBLOCK_STARTED);
if (Gp_role == GP_ROLE_DISPATCH)
{
if (!doDispatchSubtransactionInternalCmd(
DTX_PROTOCOL_COMMAND_SUBTRANSACTION_ROLLBACK_INTERNAL))
{
ereport(ERROR, (errcode(ERRCODE_GP_INTERCONNECTION_ERROR),
errmsg("DTX RollbackAndReleaseCurrentSubTransaction dispatch failed")));
}
}
}
/*
* AbortOutOfAnyTransaction
*
* This routine is provided for error recovery purposes. It aborts any
* active transaction or transaction block, leaving the system in a known
* idle state.
*/
void
AbortOutOfAnyTransaction(void)
{
TransactionState s = CurrentTransactionState;
/* Ensure we're not running in a doomed memory context */
AtAbort_Memory();
/*
* Greenplum specific behavior:
* Some QEs might already be in Abort State, they still need
* to reset Extension related global vars, so we invoke them
* here (not AbortTransction).
*/
if (Gp_role == GP_ROLE_EXECUTE)
ResetExtensionCreatingGlobalVarsOnQE();
/*
* Get out of any transaction or nested transaction
*/
do
{
switch (s->blockState)
{
case TBLOCK_DEFAULT:
if (s->state == TRANS_DEFAULT)
{
/* Not in a transaction, do nothing */
}
else
{
/*
* We can get here after an error during transaction start
* (state will be TRANS_START). Need to clean up the
* incompletely started transaction. First, adjust the
* low-level state to suppress warning message from
* AbortTransaction.
*/
if (s->state == TRANS_START)
s->state = TRANS_INPROGRESS;
AbortTransaction();
CleanupTransaction();
}
break;
case TBLOCK_STARTED:
case TBLOCK_BEGIN:
case TBLOCK_INPROGRESS:
case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_PREPARE:
/* In a transaction, so clean up */
AbortTransaction();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
Assert(DistributedTransactionContext == DTX_CONTEXT_LOCAL_ONLY);
break;
case TBLOCK_ABORT:
case TBLOCK_ABORT_END:
/*
* AbortTransaction is already done, still need Cleanup.
* However, if we failed partway through running ROLLBACK,
* there will be an active portal running that command, which
* we need to shut down before doing CleanupTransaction.
*/
AtAbort_Portals();
CleanupTransaction();
s->blockState = TBLOCK_DEFAULT;
Assert(DistributedTransactionContext == DTX_CONTEXT_LOCAL_ONLY);
break;
/*
* In a subtransaction, so clean it up and abort parent too
*/
case TBLOCK_SUBBEGIN:
case TBLOCK_SUBINPROGRESS:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
AbortSubTransaction();
CleanupSubTransaction();
s = CurrentTransactionState; /* changed by pop */
break;
case TBLOCK_SUBABORT:
case TBLOCK_SUBABORT_END:
case TBLOCK_SUBABORT_RESTART:
/* As above, but AbortSubTransaction already done */
if (s->curTransactionOwner)
{
/* As in TBLOCK_ABORT, might have a live portal to zap */
AtSubAbort_Portals(s->subTransactionId,
s->parent->subTransactionId,
s->curTransactionOwner,
s->parent->curTransactionOwner);
}
CleanupSubTransaction();
s = CurrentTransactionState; /* changed by pop */
break;
}
} while (s->blockState != TBLOCK_DEFAULT);
/* Should be out of all subxacts now */
Assert(s->parent == NULL);
/* If we didn't actually have anything to do, revert to TopMemoryContext */
AtCleanup_Memory();
}
/*
* IsTransactionBlock --- are we within a transaction block?
*/
bool
IsTransactionBlock(void)
{
TransactionState s = CurrentTransactionState;
if (s->blockState == TBLOCK_DEFAULT || s->blockState == TBLOCK_STARTED)
return false;
return true;
}
/*
* IsTransactionOrTransactionBlock --- are we within either a transaction
* or a transaction block? (The backend is only really "idle" when this
* returns false.)
*
* This should match up with IsTransactionBlock and IsTransactionState.
*/
bool
IsTransactionOrTransactionBlock(void)
{
TransactionState s = CurrentTransactionState;
if (s->blockState == TBLOCK_DEFAULT)
return false;
return true;
}
void
ExecutorMarkTransactionUsesSequences(void)
{
seqXlogWrite = true;
ForceSyncCommit();
}
void
ExecutorMarkTransactionDoesWrites(void)
{
// UNDONE: Verify we are in transaction...
if (!TopTransactionStateData.executorSaysXactDoesWrites)
{
ereportif(Debug_print_full_dtm, LOG,
(errmsg("ExecutorMarkTransactionDoesWrites called")));
TopTransactionStateData.executorSaysXactDoesWrites = true;
}
}
bool
ExecutorSaysTransactionDoesWrites(void)
{
return TopTransactionStateData.executorSaysXactDoesWrites;
}
/*
* TransactionBlockStatusCode - return status code to send in ReadyForQuery
*/
char
TransactionBlockStatusCode(void)
{
TransactionState s = CurrentTransactionState;
switch (s->blockState)
{
case TBLOCK_DEFAULT:
case TBLOCK_STARTED:
return 'I'; /* idle --- not in transaction */
case TBLOCK_BEGIN:
case TBLOCK_SUBBEGIN:
case TBLOCK_INPROGRESS:
case TBLOCK_IMPLICIT_INPROGRESS:
case TBLOCK_PARALLEL_INPROGRESS:
case TBLOCK_SUBINPROGRESS:
case TBLOCK_END:
case TBLOCK_SUBRELEASE:
case TBLOCK_SUBCOMMIT:
case TBLOCK_PREPARE:
return 'T'; /* in transaction */
case TBLOCK_ABORT:
case TBLOCK_SUBABORT:
case TBLOCK_ABORT_END:
case TBLOCK_SUBABORT_END:
case TBLOCK_ABORT_PENDING:
case TBLOCK_SUBABORT_PENDING:
case TBLOCK_SUBRESTART:
case TBLOCK_SUBABORT_RESTART:
return 'E'; /* in failed transaction */
}
/* should never get here */
elog(FATAL, "invalid transaction block state: %s",
BlockStateAsString(s->blockState));
return 0; /* keep compiler quiet */
}
/*
* IsSubTransaction
*/
bool
IsSubTransaction(void)
{
TransactionState s = CurrentTransactionState;
if (s->nestingLevel >= 2)
return true;
return false;
}
/*
* StartSubTransaction
*
* If you're wondering why this is separate from PushTransaction: it's because
* we can't conveniently do this stuff right inside DefineSavepoint. The
* SAVEPOINT utility command will be executed inside a Portal, and if we
* muck with CurrentMemoryContext or CurrentResourceOwner then exit from
* the Portal will undo those settings. So we make DefineSavepoint just
* push a dummy transaction block, and when control returns to the main
* idle loop, CommitTransactionCommand will be called, and we'll come here
* to finish starting the subtransaction.
*/
static void
StartSubTransaction(void)
{
TransactionState s = CurrentTransactionState;
if (s->state != TRANS_DEFAULT)
elog(WARNING, "StartSubTransaction while in %s state",
TransStateAsString(s->state));
s->state = TRANS_START;
/*
* Initialize subsystems for new subtransaction
*
* must initialize resource-management stuff first
*/
AtSubStart_Memory();
AtSubStart_ResourceOwner();
AtSubStart_Notify();
AfterTriggerBeginSubXact();
s->state = TRANS_INPROGRESS;
/*
* Call start-of-subxact callbacks
*/
CallSubXactCallbacks(SUBXACT_EVENT_START_SUB, s->subTransactionId,
s->parent->subTransactionId);
ShowTransactionState("StartSubTransaction");
}
/*
* CommitSubTransaction
*
* The caller has to make sure to always reassign CurrentTransactionState
* if it has a local pointer to it after calling this function.
*/
static void
CommitSubTransaction(void)
{
TransactionState s = CurrentTransactionState;
ShowTransactionState("CommitSubTransaction");
if (s->state != TRANS_INPROGRESS)
elog(WARNING, "CommitSubTransaction while in %s state",
TransStateAsString(s->state));
/* Pre-commit processing goes here */
CallSubXactCallbacks(SUBXACT_EVENT_PRE_COMMIT_SUB, s->subTransactionId,
s->parent->subTransactionId);
/* If in parallel mode, clean up workers and exit parallel mode. */
if (IsInParallelMode())
{
AtEOSubXact_Parallel(true, s->subTransactionId);
s->parallelModeLevel = 0;
}
/* Do the actual "commit", such as it is */
s->state = TRANS_COMMIT;
/* Must CCI to ensure commands of subtransaction are seen as done */
CommandCounterIncrement();
/*
* Prior to 8.4 we marked subcommit in clog at this point. We now only
* perform that step, if required, as part of the atomic update of the
* whole transaction tree at top level commit or abort.
*/
/* Post-commit cleanup */
if (FullTransactionIdIsValid(s->fullTransactionId))
AtSubCommit_childXids();
AfterTriggerEndSubXact(true);
AtSubCommit_Portals(s->subTransactionId,
s->parent->subTransactionId,
s->parent->curTransactionOwner);
AtEOSubXact_LargeObject(true, s->subTransactionId,
s->parent->subTransactionId);
AtSubCommit_Notify();
CallSubXactCallbacks(SUBXACT_EVENT_COMMIT_SUB, s->subTransactionId,
s->parent->subTransactionId);
ResourceOwnerRelease(s->curTransactionOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
true, false);
AtEOSubXact_RelationCache(true, s->subTransactionId,
s->parent->subTransactionId);
AtEOSubXact_Inval(true);
AtSubCommit_smgr();
/*
* The only lock we actually release here is the subtransaction XID lock.
*/
CurrentResourceOwner = s->curTransactionOwner;
if (FullTransactionIdIsValid(s->fullTransactionId))
XactLockTableDelete(XidFromFullTransactionId(s->fullTransactionId));
/*
* Other locks should get transferred to their parent resource owner.
*/
ResourceOwnerRelease(s->curTransactionOwner,
RESOURCE_RELEASE_LOCKS,
true, false);
ResourceOwnerRelease(s->curTransactionOwner,
RESOURCE_RELEASE_AFTER_LOCKS,
true, false);
AtEOXact_GUC(true, s->gucNestLevel);
AtEOSubXact_SPI(true, s->subTransactionId);
AtEOSubXact_on_commit_actions(true, s->subTransactionId,
s->parent->subTransactionId);
AtEOSubXact_Namespace(true, s->subTransactionId,
s->parent->subTransactionId);
AtEOSubXact_Files(true, s->subTransactionId,
s->parent->subTransactionId);
AtEOSubXact_HashTables(true, s->nestingLevel);
AtEOSubXact_PgStat(true, s->nestingLevel);
AtSubCommit_Snapshot(s->nestingLevel);
AtEOSubXact_ApplyLauncher(true, s->nestingLevel);
/*
* We need to restore the upper transaction's read-only state, in case the
* upper is read-write while the child is read-only; GUC will incorrectly
* think it should leave the child state in place.
*/
XactReadOnly = s->prevXactReadOnly;
CurrentResourceOwner = s->parent->curTransactionOwner;
CurTransactionResourceOwner = s->parent->curTransactionOwner;
ResourceOwnerDelete(s->curTransactionOwner);
s->curTransactionOwner = NULL;
AtSubCommit_Memory();
s->state = TRANS_DEFAULT;
PopTransaction();
}
/*
* AbortSubTransaction
*/
static void
AbortSubTransaction(void)
{
TransactionState s = CurrentTransactionState;
/* Prevent cancel/die interrupt while cleaning up */
HOLD_INTERRUPTS();
/* Make sure we have a valid memory context and resource owner */
AtSubAbort_Memory();
AtSubAbort_ResourceOwner();
/*
* Release any LW locks we might be holding as quickly as possible.
* (Regular locks, however, must be held till we finish aborting.)
* Releasing LW locks is critical since we might try to grab them again
* while cleaning up!
*
* FIXME This may be incorrect --- Are there some locks we should keep?
* Buffer locks, for example? I don't think so but I'm not sure.
*/
LWLockReleaseAll();
pgstat_report_wait_end();
pgstat_progress_end_command();
AbortBufferIO();
UnlockBuffers();
/* Reset WAL record construction state */
XLogResetInsertion();
/* Cancel condition variable sleep */
ConditionVariableCancelSleep();
/*
* Also clean up any open wait for lock, since the lock manager will choke
* if we try to wait for another lock before doing this.
*/
LockErrorCleanup();
/*
* If any timeout events are still active, make sure the timeout interrupt
* is scheduled. This covers possible loss of a timeout interrupt due to
* longjmp'ing out of the SIGINT handler (see notes in handle_sig_alarm).
* We delay this till after LockErrorCleanup so that we don't uselessly
* reschedule lock or deadlock check timeouts.
*/
reschedule_timeouts();
/*
* Re-enable signals, in case we got here by longjmp'ing out of a signal
* handler. We do this fairly early in the sequence so that the timeout
* infrastructure will be functional if needed while aborting.
*/
PG_SETMASK(&UnBlockSig);
/*
* check the current transaction state
*/
ShowTransactionState("AbortSubTransaction");
if (s->state != TRANS_INPROGRESS)
elog(WARNING, "AbortSubTransaction while in %s state",
TransStateAsString(s->state));
s->state = TRANS_ABORT;
/*
* Reset user ID which might have been changed transiently. (See notes in
* AbortTransaction.)
*/
SetUserIdAndSecContext(s->prevUser, s->prevSecContext);
/* Exit from parallel mode, if necessary. */
if (IsInParallelMode())
{
AtEOSubXact_Parallel(false, s->subTransactionId);
s->parallelModeLevel = 0;
}
/*
* We can skip all this stuff if the subxact failed before creating a
* ResourceOwner...
*/
if (s->curTransactionOwner)
{
AfterTriggerEndSubXact(false);
AtSubAbort_Portals(s->subTransactionId,
s->parent->subTransactionId,
s->curTransactionOwner,
s->parent->curTransactionOwner);
AtSubAbort_DispatcherState();
AtEOXact_DispatchOids(false);
AtEOSubXact_LargeObject(false, s->subTransactionId,
s->parent->subTransactionId);
AtSubAbort_Notify();
/* Advertise the fact that we aborted in pg_xact. */
(void) RecordTransactionAbort(true);
/* Post-abort cleanup */
if (FullTransactionIdIsValid(s->fullTransactionId))
AtSubAbort_childXids();
CallSubXactCallbacks(SUBXACT_EVENT_ABORT_SUB, s->subTransactionId,
s->parent->subTransactionId);
ResourceOwnerRelease(s->curTransactionOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, false);
AtEOSubXact_RelationCache(false, s->subTransactionId,
s->parent->subTransactionId);
AtEOSubXact_Inval(false);
ResourceOwnerRelease(s->curTransactionOwner,
RESOURCE_RELEASE_LOCKS,
false, false);
ResourceOwnerRelease(s->curTransactionOwner,
RESOURCE_RELEASE_AFTER_LOCKS,
false, false);
AtSubAbort_smgr();
AtEOXact_GUC(false, s->gucNestLevel);
AtEOSubXact_SPI(false, s->subTransactionId);
AtEOSubXact_on_commit_actions(false, s->subTransactionId,
s->parent->subTransactionId);
AtEOSubXact_Namespace(false, s->subTransactionId,
s->parent->subTransactionId);
AtEOSubXact_Files(false, s->subTransactionId,
s->parent->subTransactionId);
AtEOSubXact_HashTables(false, s->nestingLevel);
AtEOSubXact_PgStat(false, s->nestingLevel);
AtSubAbort_Snapshot(s->nestingLevel);
AtEOSubXact_ApplyLauncher(false, s->nestingLevel);
}
/*
* Restore the upper transaction's read-only state, too. This should be
* redundant with GUC's cleanup but we may as well do it for consistency
* with the commit case.
*/
XactReadOnly = s->prevXactReadOnly;
RESUME_INTERRUPTS();
}
/*
* CleanupSubTransaction
*
* The caller has to make sure to always reassign CurrentTransactionState
* if it has a local pointer to it after calling this function.
*/
static void
CleanupSubTransaction(void)
{
TransactionState s = CurrentTransactionState;
ShowTransactionState("CleanupSubTransaction");
if (s->state != TRANS_ABORT)
elog(WARNING, "CleanupSubTransaction while in %s state",
TransStateAsString(s->state));
AtSubCleanup_Portals(s->subTransactionId);
CurrentResourceOwner = s->parent->curTransactionOwner;
CurTransactionResourceOwner = s->parent->curTransactionOwner;
if (s->curTransactionOwner)
ResourceOwnerDelete(s->curTransactionOwner);
s->curTransactionOwner = NULL;
AtSubCleanup_Memory();
s->state = TRANS_DEFAULT;
PopTransaction();
}
/*
* PushTransaction
* Create transaction state stack entry for a subtransaction
*
* The caller has to make sure to always reassign CurrentTransactionState
* if it has a local pointer to it after calling this function.
*/
static void
PushTransaction(void)
{
TransactionState p = CurrentTransactionState;
TransactionState s;
currentSavepointTotal++;
if ((currentSavepointTotal >= gp_subtrans_warn_limit) &&
(currentSavepointTotal % gp_subtrans_warn_limit == 0))
{
ereport(WARNING,
(errmsg("Using too many subtransactions in one transaction."),
errhint("Close open transactions soon to avoid wraparound "
"problems.")));
}
/*
* We keep subtransaction state nodes in TopTransactionContext.
*/
s = (TransactionState)
MemoryContextAllocZero(TopTransactionContext,
sizeof(TransactionStateData));
/*
* Assign a subtransaction ID, watching out for counter wraparound.
*/
currentSubTransactionId += 1;
if (currentSubTransactionId == InvalidSubTransactionId)
{
currentSubTransactionId -= 1;
pfree(s);
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("cannot have more than 2^32-1 subtransactions in a transaction")));
}
/*
* We can now stack a minimally valid subtransaction without fear of
* failure.
*/
s->fullTransactionId = InvalidFullTransactionId; /* until assigned */
s->subTransactionId = currentSubTransactionId;
s->parent = p;
s->nestingLevel = p->nestingLevel + 1;
s->gucNestLevel = NewGUCNestLevel();
s->savepointLevel = p->savepointLevel;
s->state = TRANS_DEFAULT;
s->blockState = TBLOCK_SUBBEGIN;
GetUserIdAndSecContext(&s->prevUser, &s->prevSecContext);
s->prevXactReadOnly = XactReadOnly;
s->parallelModeLevel = 0;
s->executorSaysXactDoesWrites = false;
fastNodeCount++;
if (fastNodeCount == NUM_NODES_TO_SKIP_FOR_FAST_SEARCH)
{
fastNodeCount = 0;
s->fastLink = previousFastLink;
previousFastLink = s;
}
CurrentTransactionState = s;
/*
* AbortSubTransaction and CleanupSubTransaction have to be able to cope
* with the subtransaction from here on out; in particular they should not
* assume that it necessarily has a transaction context, resource owner,
* or XID.
*/
}
/*
* PopTransaction
* Pop back to parent transaction state
*
* The caller has to make sure to always reassign CurrentTransactionState
* if it has a local pointer to it after calling this function.
*/
static void
PopTransaction(void)
{
TransactionState s = CurrentTransactionState;
if (s->state != TRANS_DEFAULT)
elog(WARNING, "PopTransaction while in %s state",
TransStateAsString(s->state));
if (s->parent == NULL)
elog(FATAL, "PopTransaction with no parent");
CurrentTransactionState = s->parent;
/* Let's just make sure CurTransactionContext is good */
CurTransactionContext = s->parent->curTransactionContext;
MemoryContextSwitchTo(CurTransactionContext);
/* Ditto for ResourceOwner links */
CurTransactionResourceOwner = s->parent->curTransactionOwner;
CurrentResourceOwner = s->parent->curTransactionOwner;
if (fastNodeCount)
{
fastNodeCount--;
}
/*
* Deleting node where last fastLink is stored
* hence retrive the fastLink to update in node to be added next
*/
if (previousFastLink == s)
{
fastNodeCount = NUM_NODES_TO_SKIP_FOR_FAST_SEARCH - 1;
previousFastLink = s->fastLink;
}
/* Free the old child structure */
if (s->name)
pfree(s->name);
pfree(s);
}
/*
* EstimateTransactionStateSpace
* Estimate the amount of space that will be needed by
* SerializeTransactionState. It would be OK to overestimate slightly,
* but it's simple for us to work out the precise value, so we do.
*/
Size
EstimateTransactionStateSpace(void)
{
TransactionState s;
Size nxids = 0;
Size size = SerializedTransactionStateHeaderSize;
for (s = CurrentTransactionState; s != NULL; s = s->parent)
{
if (FullTransactionIdIsValid(s->fullTransactionId))
nxids = add_size(nxids, 1);
nxids = add_size(nxids, s->nChildXids);
}
return add_size(size, mul_size(sizeof(TransactionId), nxids));
}
/*
* SerializeTransactionState
* Write out relevant details of our transaction state that will be
* needed by a parallel worker.
*
* We need to save and restore XactDeferrable, XactIsoLevel, and the XIDs
* associated with this transaction. These are serialized into a
* caller-supplied buffer big enough to hold the number of bytes reported by
* EstimateTransactionStateSpace(). We emit the XIDs in sorted order for the
* convenience of the receiving process.
*/
void
SerializeTransactionState(Size maxsize, char *start_address)
{
TransactionState s;
Size nxids = 0;
Size i = 0;
TransactionId *workspace;
SerializedTransactionState *result;
result = (SerializedTransactionState *) start_address;
result->xactIsoLevel = XactIsoLevel;
result->xactDeferrable = XactDeferrable;
result->topFullTransactionId = XactTopFullTransactionId;
result->currentFullTransactionId =
CurrentTransactionState->fullTransactionId;
result->currentCommandId = currentCommandId;
/*
* If we're running in a parallel worker and launching a parallel worker
* of our own, we can just pass along the information that was passed to
* us.
*/
if (nParallelCurrentXids > 0)
{
result->nParallelCurrentXids = nParallelCurrentXids;
memcpy(&result->parallelCurrentXids[0], ParallelCurrentXids,
nParallelCurrentXids * sizeof(TransactionId));
return;
}
/*
* OK, we need to generate a sorted list of XIDs that our workers should
* view as current. First, figure out how many there are.
*/
for (s = CurrentTransactionState; s != NULL; s = s->parent)
{
if (FullTransactionIdIsValid(s->fullTransactionId))
nxids = add_size(nxids, 1);
nxids = add_size(nxids, s->nChildXids);
}
Assert(SerializedTransactionStateHeaderSize + nxids * sizeof(TransactionId)
<= maxsize);
/* Copy them to our scratch space. */
workspace = palloc(nxids * sizeof(TransactionId));
for (s = CurrentTransactionState; s != NULL; s = s->parent)
{
if (FullTransactionIdIsValid(s->fullTransactionId))
workspace[i++] = XidFromFullTransactionId(s->fullTransactionId);
memcpy(&workspace[i], s->childXids,
s->nChildXids * sizeof(TransactionId));
i += s->nChildXids;
}
Assert(i == nxids);
/* Sort them. */
qsort(workspace, nxids, sizeof(TransactionId), xidComparator);
/* Copy data into output area. */
result->nParallelCurrentXids = nxids;
memcpy(&result->parallelCurrentXids[0], workspace,
nxids * sizeof(TransactionId));
}
/*
* StartParallelWorkerTransaction
* Start a parallel worker transaction, restoring the relevant
* transaction state serialized by SerializeTransactionState.
*/
void
StartParallelWorkerTransaction(char *tstatespace)
{
SerializedTransactionState *tstate;
Assert(CurrentTransactionState->blockState == TBLOCK_DEFAULT);
StartTransaction();
tstate = (SerializedTransactionState *) tstatespace;
XactIsoLevel = tstate->xactIsoLevel;
XactDeferrable = tstate->xactDeferrable;
XactTopFullTransactionId = tstate->topFullTransactionId;
CurrentTransactionState->fullTransactionId =
tstate->currentFullTransactionId;
currentCommandId = tstate->currentCommandId;
nParallelCurrentXids = tstate->nParallelCurrentXids;
ParallelCurrentXids = &tstate->parallelCurrentXids[0];
CurrentTransactionState->blockState = TBLOCK_PARALLEL_INPROGRESS;
}
/*
* EndParallelWorkerTransaction
* End a parallel worker transaction.
*/
void
EndParallelWorkerTransaction(void)
{
Assert(CurrentTransactionState->blockState == TBLOCK_PARALLEL_INPROGRESS);
CommitTransaction();
CurrentTransactionState->blockState = TBLOCK_DEFAULT;
}
/*
* ShowTransactionState
* Debug support
*/
static void
ShowTransactionState(const char *str)
{
/* skip work if message will definitely not be printed */
if (log_min_messages <= DEBUG5 || client_min_messages <= DEBUG5)
ShowTransactionStateRec(str, CurrentTransactionState);
}
/*
* ShowTransactionStateRec
* Recursive subroutine for ShowTransactionState
*/
static void
ShowTransactionStateRec(const char *str, TransactionState s)
{
StringInfoData buf;
initStringInfo(&buf);
if (s->nChildXids > 0)
{
int i;
appendStringInfo(&buf, ", children: %u", s->childXids[0]);
for (i = 1; i < s->nChildXids; i++)
appendStringInfo(&buf, " %u", s->childXids[i]);
}
if (s->parent)
ShowTransactionStateRec(str, s->parent);
/* use ereport to suppress computation if msg will not be printed */
ereport(DEBUG5,
(errmsg_internal("%s(%d) name: %s; blockState: %s; state: %s, xid/subid/cid: %u/%u/%u%s%s",
str, s->nestingLevel,
PointerIsValid(s->name) ? s->name : "unnamed",
BlockStateAsString(s->blockState),
TransStateAsString(s->state),
(unsigned int) XidFromFullTransactionId(s->fullTransactionId),
(unsigned int) s->subTransactionId,
(unsigned int) currentCommandId,
currentCommandIdUsed ? " (used)" : "",
buf.data)));
pfree(buf.data);
}
/*
* BlockStateAsString
* Debug support
*/
static const char *
BlockStateAsString(TBlockState blockState)
{
switch (blockState)
{
case TBLOCK_DEFAULT:
return "DEFAULT";
case TBLOCK_STARTED:
return "STARTED";
case TBLOCK_BEGIN:
return "BEGIN";
case TBLOCK_INPROGRESS:
return "INPROGRESS";
case TBLOCK_IMPLICIT_INPROGRESS:
return "IMPLICIT_INPROGRESS";
case TBLOCK_PARALLEL_INPROGRESS:
return "PARALLEL_INPROGRESS";
case TBLOCK_END:
return "END";
case TBLOCK_ABORT:
return "ABORT";
case TBLOCK_ABORT_END:
return "ABORT_END";
case TBLOCK_ABORT_PENDING:
return "ABORT_PENDING";
case TBLOCK_PREPARE:
return "PREPARE";
case TBLOCK_SUBBEGIN:
return "SUBBEGIN";
case TBLOCK_SUBINPROGRESS:
return "SUBINPROGRESS";
case TBLOCK_SUBRELEASE:
return "SUBRELEASE";
case TBLOCK_SUBCOMMIT:
return "SUBCOMMIT";
case TBLOCK_SUBABORT:
return "SUBABORT";
case TBLOCK_SUBABORT_END:
return "SUBABORT_END";
case TBLOCK_SUBABORT_PENDING:
return "SUBABORT_PENDING";
case TBLOCK_SUBRESTART:
return "SUBRESTART";
case TBLOCK_SUBABORT_RESTART:
return "SUBABORT_RESTART";
}
return "UNRECOGNIZED";
}
/*
* TransStateAsString
* Debug support
*/
static const char *
TransStateAsString(TransState state)
{
switch (state)
{
case TRANS_DEFAULT:
return "DEFAULT";
case TRANS_START:
return "START";
case TRANS_INPROGRESS:
return "INPROGRESS";
case TRANS_COMMIT:
return "COMMIT";
case TRANS_ABORT:
return "ABORT";
case TRANS_PREPARE:
return "PREPARE";
}
return "UNRECOGNIZED";
}
/*
* EndLocalDistribXact
*/
static void
EndLocalDistribXact(bool isCommit)
{
if (MyProc->localDistribXactData.state == LOCALDISTRIBXACT_STATE_NONE)
return;
/*
* MyProc->localDistribXactData is access by backend itself only hence okay
* to modify without holding the lock.
*/
switch (DistributedTransactionContext)
{
case DTX_CONTEXT_QE_TWO_PHASE_EXPLICIT_WRITER:
case DTX_CONTEXT_QE_TWO_PHASE_IMPLICIT_WRITER:
case DTX_CONTEXT_QE_AUTO_COMMIT_IMPLICIT:
case DTX_CONTEXT_QD_DISTRIBUTED_CAPABLE:
case DTX_CONTEXT_QD_RETRY_PHASE_2:
case DTX_CONTEXT_LOCAL_ONLY:
AssertImply(DistributedTransactionContext == DTX_CONTEXT_LOCAL_ONLY,
Gp_role == GP_ROLE_UTILITY || IsAutoVacuumWorkerProcess());
LocalDistribXact_ChangeState(MyProc->pgprocno,
isCommit ?
LOCALDISTRIBXACT_STATE_COMMITTED :
LOCALDISTRIBXACT_STATE_ABORTED);
break;
case DTX_CONTEXT_QE_READER:
case DTX_CONTEXT_QE_ENTRY_DB_SINGLETON:
// QD or QE Writer will handle it.
break;
case DTX_CONTEXT_QE_PREPARED:
case DTX_CONTEXT_QE_FINISH_PREPARED:
elog(PANIC, "Unexpected distribute transaction context: '%s'",
DtxContextToString(DistributedTransactionContext));
break;
default:
elog(PANIC, "Unrecognized DTX transaction context: %d",
(int) DistributedTransactionContext);
break;
}
}
/*
* IsoLevelAsUpperString
* Formatting helper.
*/
const char *
IsoLevelAsUpperString(int IsoLevel)
{
switch (IsoLevel)
{
case XACT_READ_UNCOMMITTED:
return "READ UNCOMMITTED";
case XACT_READ_COMMITTED:
return "READ COMMITTED";
case XACT_REPEATABLE_READ:
return "REPEATABLE READ";
case XACT_SERIALIZABLE:
return "SERIALIZABLE";
default:
return "UNKNOWN";
}
}
/*
* xactGetCommittedChildren
*
* Gets the list of committed children of the current transaction. The return
* value is the number of child transactions. *ptr is set to point to an
* array of TransactionIds. The array is allocated in TopTransactionContext;
* the caller should *not* pfree() it (this is a change from pre-8.4 code!).
* If there are no subxacts, *ptr is set to NULL.
*/
int
xactGetCommittedChildren(TransactionId **ptr)
{
TransactionState s = CurrentTransactionState;
if (s->nChildXids == 0)
*ptr = NULL;
else
*ptr = s->childXids;
return s->nChildXids;
}
/*
* Log the commit record for a plain or twophase transaction commit.
*
* A 2pc commit will be emitted when twophase_xid is valid, a plain one
* otherwise.
*/
XLogRecPtr
XactLogCommitRecord(TimestampTz commit_time,
Oid tablespace_oid_to_delete_on_commit,
int nsubxacts, TransactionId *subxacts,
int nrels, RelFileNodePendingDelete *rels,
int nmsgs, SharedInvalidationMessage *msgs,
int ndeldbs, DbDirNode *deldbs,
bool relcacheInval, bool forceSync,
int xactflags, TransactionId twophase_xid,
const char *twophase_gid)
{
xl_xact_commit xlrec;
xl_xact_xinfo xl_xinfo;
xl_xact_dbinfo xl_dbinfo;
xl_xact_subxacts xl_subxacts;
xl_xact_relfilenodes xl_relfilenodes;
xl_xact_invals xl_invals;
xl_xact_twophase xl_twophase;
xl_xact_origin xl_origin;
xl_xact_distrib xl_distrib;
xl_xact_deldbs xl_deldbs;
XLogRecPtr recptr;
bool isOnePhaseQE = (Gp_role == GP_ROLE_EXECUTE && MyTmGxactLocal->isOnePhaseCommit);
bool isDtxPrepared = isPreparedDtxTransaction();
uint8 info;
Assert(CritSectionCount > 0);
xl_xinfo.xinfo = 0;
/* decide between a plain and 2pc commit */
if (isDtxPrepared)
info = XLOG_XACT_DISTRIBUTED_COMMIT;
else if (!TransactionIdIsValid(twophase_xid))
info = XLOG_XACT_COMMIT;
else
info = XLOG_XACT_COMMIT_PREPARED;
/* First figure out and collect all the information needed */
xlrec.xact_time = commit_time;
xlrec.tablespace_oid_to_delete_on_commit = tablespace_oid_to_delete_on_commit;
if (relcacheInval)
xl_xinfo.xinfo |= XACT_COMPLETION_UPDATE_RELCACHE_FILE;
if (forceSyncCommit)
xl_xinfo.xinfo |= XACT_COMPLETION_FORCE_SYNC_COMMIT;
if ((xactflags & XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK))
xl_xinfo.xinfo |= XACT_XINFO_HAS_AE_LOCKS;
/*
* Check if the caller would like to ask standbys for immediate feedback
* once this commit is applied.
*/
if (synchronous_commit >= SYNCHRONOUS_COMMIT_REMOTE_APPLY)
xl_xinfo.xinfo |= XACT_COMPLETION_APPLY_FEEDBACK;
/*
* Relcache invalidations requires information about the current database
* and so does logical decoding.
*/
if (nmsgs > 0 || XLogLogicalInfoActive())
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_DBINFO;
xl_dbinfo.dbId = MyDatabaseId;
xl_dbinfo.tsId = MyDatabaseTableSpace;
}
if (nsubxacts > 0)
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_SUBXACTS;
xl_subxacts.nsubxacts = nsubxacts;
}
if (nrels > 0)
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_RELFILENODES;
xl_relfilenodes.nrels = nrels;
}
if (nmsgs > 0)
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_INVALS;
xl_invals.nmsgs = nmsgs;
}
if (ndeldbs > 0)
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_DELDBS;
xl_deldbs.ndeldbs = ndeldbs;
}
if (TransactionIdIsValid(twophase_xid))
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_TWOPHASE;
xl_twophase.xid = twophase_xid;
Assert(twophase_gid != NULL);
if (XLogLogicalInfoActive())
xl_xinfo.xinfo |= XACT_XINFO_HAS_GID;
}
/* dump transaction origin information */
if (replorigin_session_origin != InvalidRepOriginId)
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_ORIGIN;
xl_origin.origin_lsn = replorigin_session_origin_lsn;
xl_origin.origin_timestamp = replorigin_session_origin_timestamp;
}
if (isDtxPrepared || isOnePhaseQE)
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_DISTRIB;
xl_distrib.distrib_xid = getDistributedTransactionId();
}
if (xl_xinfo.xinfo != 0)
info |= XLOG_XACT_HAS_INFO;
/* Then include all the collected data into the commit record. */
XLogBeginInsert();
XLogRegisterData((char *) (&xlrec), sizeof(xl_xact_commit));
if (xl_xinfo.xinfo != 0)
XLogRegisterData((char *) (&xl_xinfo.xinfo), sizeof(xl_xinfo.xinfo));
if (xl_xinfo.xinfo & XACT_XINFO_HAS_DBINFO)
XLogRegisterData((char *) (&xl_dbinfo), sizeof(xl_dbinfo));
if (xl_xinfo.xinfo & XACT_XINFO_HAS_SUBXACTS)
{
XLogRegisterData((char *) (&xl_subxacts),
MinSizeOfXactSubxacts);
XLogRegisterData((char *) subxacts,
nsubxacts * sizeof(TransactionId));
}
if (xl_xinfo.xinfo & XACT_XINFO_HAS_RELFILENODES)
{
XLogRegisterData((char *) (&xl_relfilenodes),
MinSizeOfXactRelfilenodes);
XLogRegisterData((char *) rels,
nrels * sizeof(RelFileNodePendingDelete));
}
if (xl_xinfo.xinfo & XACT_XINFO_HAS_INVALS)
{
XLogRegisterData((char *) (&xl_invals), MinSizeOfXactInvals);
XLogRegisterData((char *) msgs,
nmsgs * sizeof(SharedInvalidationMessage));
}
if (xl_xinfo.xinfo & XACT_XINFO_HAS_DELDBS)
{
XLogRegisterData((char *) (&xl_deldbs), MinSizeOfXactDelDbs);
XLogRegisterData((char *) deldbs,
ndeldbs * sizeof(DbDirNode));
}
if (xl_xinfo.xinfo & XACT_XINFO_HAS_TWOPHASE)
{
XLogRegisterData((char *) (&xl_twophase), sizeof(xl_xact_twophase));
if (xl_xinfo.xinfo & XACT_XINFO_HAS_GID)
XLogRegisterData(unconstify(char *, twophase_gid), strlen(twophase_gid) + 1);
}
if (xl_xinfo.xinfo & XACT_XINFO_HAS_ORIGIN)
XLogRegisterData((char *) (&xl_origin), sizeof(xl_xact_origin));
if (xl_xinfo.xinfo & XACT_XINFO_HAS_DISTRIB)
XLogRegisterData((char *) (&xl_distrib), sizeof(xl_xact_distrib));
/* we allow filtering by xacts */
XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
if (isDtxPrepared)
insertingDistributedCommitted();
recptr = XLogInsert(RM_XACT_ID, info);
if (isDtxPrepared)
insertedDistributedCommitted();
return recptr;
}
/*
* Log the commit record for a plain or twophase transaction abort.
*
* A 2pc abort will be emitted when twophase_xid is valid, a plain one
* otherwise.
*/
XLogRecPtr
XactLogAbortRecord(TimestampTz abort_time,
Oid tablespace_oid_to_delete_on_abort,
int nsubxacts, TransactionId *subxacts,
int nrels, RelFileNodePendingDelete *rels,
int ndeldbs, DbDirNode *deldbs,
int xactflags, TransactionId twophase_xid,
const char *twophase_gid)
{
xl_xact_abort xlrec;
xl_xact_xinfo xl_xinfo;
xl_xact_subxacts xl_subxacts;
xl_xact_relfilenodes xl_relfilenodes;
xl_xact_deldbs xl_deldbs;
xl_xact_twophase xl_twophase;
xl_xact_dbinfo xl_dbinfo;
xl_xact_origin xl_origin;
uint8 info;
Assert(CritSectionCount > 0);
xl_xinfo.xinfo = 0;
/* decide between a plain and 2pc abort */
if (!TransactionIdIsValid(twophase_xid))
info = XLOG_XACT_ABORT;
else
info = XLOG_XACT_ABORT_PREPARED;
/* First figure out and collect all the information needed */
xlrec.xact_time = abort_time;
xlrec.tablespace_oid_to_delete_on_abort = tablespace_oid_to_delete_on_abort;
if ((xactflags & XACT_FLAGS_ACQUIREDACCESSEXCLUSIVELOCK))
xl_xinfo.xinfo |= XACT_XINFO_HAS_AE_LOCKS;
if (nsubxacts > 0)
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_SUBXACTS;
xl_subxacts.nsubxacts = nsubxacts;
}
if (nrels > 0)
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_RELFILENODES;
xl_relfilenodes.nrels = nrels;
}
if (ndeldbs > 0)
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_DELDBS;
xl_deldbs.ndeldbs = ndeldbs;
}
if (TransactionIdIsValid(twophase_xid))
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_TWOPHASE;
xl_twophase.xid = twophase_xid;
Assert(twophase_gid != NULL);
if (XLogLogicalInfoActive())
xl_xinfo.xinfo |= XACT_XINFO_HAS_GID;
}
if (TransactionIdIsValid(twophase_xid) && XLogLogicalInfoActive())
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_DBINFO;
xl_dbinfo.dbId = MyDatabaseId;
xl_dbinfo.tsId = MyDatabaseTableSpace;
}
/* dump transaction origin information only for abort prepared */
if ((replorigin_session_origin != InvalidRepOriginId) &&
TransactionIdIsValid(twophase_xid) &&
XLogLogicalInfoActive())
{
xl_xinfo.xinfo |= XACT_XINFO_HAS_ORIGIN;
xl_origin.origin_lsn = replorigin_session_origin_lsn;
xl_origin.origin_timestamp = replorigin_session_origin_timestamp;
}
if (xl_xinfo.xinfo != 0)
info |= XLOG_XACT_HAS_INFO;
/* Then include all the collected data into the abort record. */
XLogBeginInsert();
XLogRegisterData((char *) (&xlrec), MinSizeOfXactAbort);
if (xl_xinfo.xinfo != 0)
XLogRegisterData((char *) (&xl_xinfo), sizeof(xl_xinfo));
if (xl_xinfo.xinfo & XACT_XINFO_HAS_DBINFO)
XLogRegisterData((char *) (&xl_dbinfo), sizeof(xl_dbinfo));
if (xl_xinfo.xinfo & XACT_XINFO_HAS_SUBXACTS)
{
XLogRegisterData((char *) (&xl_subxacts),
MinSizeOfXactSubxacts);
XLogRegisterData((char *) subxacts,
nsubxacts * sizeof(TransactionId));
}
if (xl_xinfo.xinfo & XACT_XINFO_HAS_RELFILENODES)
{
XLogRegisterData((char *) (&xl_relfilenodes),
MinSizeOfXactRelfilenodes);
XLogRegisterData((char *) rels,
nrels * sizeof(RelFileNodePendingDelete));
}
if (xl_xinfo.xinfo & XACT_XINFO_HAS_DELDBS)
{
XLogRegisterData((char *) (&xl_deldbs),
MinSizeOfXactDelDbs);
XLogRegisterData((char *) deldbs,
ndeldbs * sizeof(DbDirNode));
}
if (xl_xinfo.xinfo & XACT_XINFO_HAS_TWOPHASE)
{
XLogRegisterData((char *) (&xl_twophase), sizeof(xl_xact_twophase));
if (xl_xinfo.xinfo & XACT_XINFO_HAS_GID)
XLogRegisterData(unconstify(char *, twophase_gid), strlen(twophase_gid) + 1);
}
if (xl_xinfo.xinfo & XACT_XINFO_HAS_ORIGIN)
XLogRegisterData((char *) (&xl_origin), sizeof(xl_xact_origin));
if (TransactionIdIsValid(twophase_xid))
XLogSetRecordFlags(XLOG_INCLUDE_ORIGIN);
return XLogInsert(RM_XACT_ID, info);
}
/*
* Before 9.0 this was a fairly short function, but now it performs many
* actions for which the order of execution is critical.
*/
static void
xact_redo_commit(xl_xact_parsed_commit *parsed,
TransactionId xid,
XLogRecPtr lsn,
RepOriginId origin_id)
{
TransactionId max_xid;
TimestampTz commit_time;
Oid tablespace_oid_to_delete = parsed->tablespace_oid_to_delete_on_commit;
Assert(TransactionIdIsValid(xid));
max_xid = TransactionIdLatest(xid, parsed->nsubxacts, parsed->subxacts);
ereportif(OidIsValid(tablespace_oid_to_delete), DEBUG5,
(errmsg("in xact_redo_commit_internal with tablespace oid to delete: %u",
tablespace_oid_to_delete)));
/* Make sure nextFullXid is beyond any XID mentioned in the record. */
AdvanceNextFullTransactionIdPastXid(max_xid);
/* also update distributed commit log */
if (parsed->distribXid != 0)
{
DistributedLog_SetCommittedTree(xid, parsed->nsubxacts, parsed->subxacts,
parsed->distribXid,
/* isRedo */ true);
}
Assert(((parsed->xinfo & XACT_XINFO_HAS_ORIGIN) == 0) ==
(origin_id == InvalidRepOriginId));
if (parsed->xinfo & XACT_XINFO_HAS_ORIGIN)
commit_time = parsed->origin_timestamp;
else
commit_time = parsed->xact_time;
/* Set the transaction commit timestamp and metadata */
TransactionTreeSetCommitTsData(xid, parsed->nsubxacts, parsed->subxacts,
commit_time, origin_id, false);
if (standbyState == STANDBY_DISABLED)
{
/*
* Mark the transaction committed in pg_xact.
*/
TransactionIdCommitTree(xid, parsed->nsubxacts, parsed->subxacts);
}
else
{
/*
* If a transaction completion record arrives that has as-yet
* unobserved subtransactions then this will not have been fully
* handled by the call to RecordKnownAssignedTransactionIds() in the
* main recovery loop in xlog.c. So we need to do bookkeeping again to
* cover that case. This is confusing and it is easy to think this
* call is irrelevant, which has happened three times in development
* already. Leave it in.
*/
RecordKnownAssignedTransactionIds(max_xid);
/*
* Mark the transaction committed in pg_xact. We use async commit
* protocol during recovery to provide information on database
* consistency for when users try to set hint bits. It is important
* that we do not set hint bits until the minRecoveryPoint is past
* this commit record. This ensures that if we crash we don't see hint
* bits set on changes made by transactions that haven't yet
* recovered. It's unlikely but it's good to be safe.
*/
TransactionIdAsyncCommitTree(
xid, parsed->nsubxacts, parsed->subxacts, lsn);
/*
* We must mark clog before we update the ProcArray.
*/
ExpireTreeKnownAssignedTransactionIds(
xid, parsed->nsubxacts, parsed->subxacts, max_xid);
/*
* Send any cache invalidations attached to the commit. We must
* maintain the same order of invalidation then release locks as
* occurs in CommitTransaction().
*/
ProcessCommittedInvalidationMessages(
parsed->msgs, parsed->nmsgs,
XactCompletionRelcacheInitFileInval(parsed->xinfo),
parsed->dbId, parsed->tsId);
/*
* Release locks, if any. We do this for both two phase and normal one
* phase transactions. In effect we are ignoring the prepare phase and
* just going straight to lock release.
*/
if (parsed->xinfo & XACT_XINFO_HAS_AE_LOCKS)
StandbyReleaseLockTree(xid, parsed->nsubxacts, parsed->subxacts);
}
if (parsed->xinfo & XACT_XINFO_HAS_ORIGIN)
{
/* recover apply progress */
replorigin_advance(origin_id, parsed->origin_lsn, lsn,
false /* backward */ , false /* WAL */ );
}
/* Make sure files supposed to be dropped are dropped */
if (parsed->nrels > 0)
{
/*
* First update minimum recovery point to cover this WAL record. Once
* a relation is deleted, there's no going back. The buffer manager
* enforces the WAL-first rule for normal updates to relation files,
* so that the minimum recovery point is always updated before the
* corresponding change in the data file is flushed to disk, but we
* have to do the same here since we're bypassing the buffer manager.
*
* Doing this before deleting the files means that if a deletion fails
* for some reason, you cannot start up the system even after restart,
* until you fix the underlying situation so that the deletion will
* succeed. Alternatively, we could update the minimum recovery point
* after deletion, but that would leave a small window where the
* WAL-first rule would be violated.
*/
XLogFlush(lsn);
/* Make sure files supposed to be dropped are dropped */
DropRelationFiles(parsed->xnodes, parsed->nrels, true);
}
if (parsed->ndeldbs > 0)
{
XLogFlush(lsn);
DropDatabaseDirectories(parsed->deldbs, parsed->ndeldbs, true);
}
DoTablespaceDeletionForRedoXlog(tablespace_oid_to_delete);
/*
* We issue an XLogFlush() for the same reason we emit ForceSyncCommit()
* in normal operation. For example, in CREATE DATABASE, we copy all files
* from the template database, and then commit the transaction. If we
* crash after all the files have been copied but before the commit, you
* have files in the data directory without an entry in pg_database. To
* minimize the window for that, we use ForceSyncCommit() to rush the
* commit record to disk as quick as possible. We have the same window
* during recovery, and forcing an XLogFlush() (which updates
* minRecoveryPoint during recovery) helps to reduce that problem window,
* for any user that requested ForceSyncCommit().
*/
if (XactCompletionForceSyncCommit(parsed->xinfo))
XLogFlush(lsn);
/*
* If asked by the primary (because someone is waiting for a synchronous
* commit = remote_apply), we will need to ask walreceiver to send a reply
* immediately.
*/
if (XactCompletionApplyFeedback(parsed->xinfo))
XLogRequestWalReceiverReply();
}
/*
* If the xid is valid, call xact_redo_commit with the same args. The xid can
* be invalid if the distributed transaction was read-only for the Query
* Dispatcher (e.g. a DML operation like INSERT which only writes data on the
* Query Executors). Regardless, we end with recording the gxid into
* shmCommittedGxidArray which will later be removed by replaying the
* corresponding distributed forget record or resolved during promotion during
* dtx recovery.
*/
static void
xact_redo_distributed_commit(xl_xact_parsed_commit *parsed,
TransactionId xid,
XLogRecPtr lsn,
RepOriginId origin_id)
{
if (TransactionIdIsValid(xid))
xact_redo_commit(parsed, xid, lsn, origin_id);
redoDistributedCommitRecord(parsed->distribXid);
}
static void
xact_redo_abort(xl_xact_parsed_abort *parsed, TransactionId xid)
{
TransactionId max_xid;
Assert(TransactionIdIsValid(xid));
/* Make sure nextFullXid is beyond any XID mentioned in the record. */
max_xid = TransactionIdLatest(xid,
parsed->nsubxacts,
parsed->subxacts);
AdvanceNextFullTransactionIdPastXid(max_xid);
if (standbyState == STANDBY_DISABLED)
{
/* Mark the transaction aborted in pg_xact, no need for async stuff */
TransactionIdAbortTree(xid, parsed->nsubxacts, parsed->subxacts);
}
else
{
/*
* If a transaction completion record arrives that has as-yet
* unobserved subtransactions then this will not have been fully
* handled by the call to RecordKnownAssignedTransactionIds() in the
* main recovery loop in xlog.c. So we need to do bookkeeping again to
* cover that case. This is confusing and it is easy to think this
* call is irrelevant, which has happened three times in development
* already. Leave it in.
*/
RecordKnownAssignedTransactionIds(max_xid);
/* Mark the transaction aborted in pg_xact, no need for async stuff */
TransactionIdAbortTree(xid, parsed->nsubxacts, parsed->subxacts);
/*
* We must update the ProcArray after we have marked clog.
*/
ExpireTreeKnownAssignedTransactionIds(
xid, parsed->nsubxacts, parsed->subxacts, max_xid);
/*
* There are no invalidation messages to send or undo.
*/
/*
* Release locks, if any. There are no invalidations to send.
*/
if (parsed->xinfo & XACT_XINFO_HAS_AE_LOCKS)
StandbyReleaseLockTree(xid, parsed->nsubxacts, parsed->subxacts);
}
/* Make sure files supposed to be dropped are dropped */
DropRelationFiles(parsed->xnodes, parsed->nrels, true);
DropDatabaseDirectories(parsed->deldbs, parsed->ndeldbs, true);
DoTablespaceDeletionForRedoXlog(parsed->tablespace_oid_to_delete_on_abort);
}
static void
xact_redo_distributed_forget(xl_xact_distributed_forget *xlrec, TransactionId xid pg_attribute_unused() )
{
redoDistributedForgetCommitRecord(xlrec->gxid);
}
void
xact_redo(XLogReaderState *record)
{
uint8 info = XLogRecGetInfo(record) & XLOG_XACT_OPMASK;
/* Backup blocks are not used in xact records */
Assert(!XLogRecHasAnyBlockRefs(record));
if (info == XLOG_XACT_COMMIT)
{
xl_xact_commit *xlrec = (xl_xact_commit *) XLogRecGetData(record);
xl_xact_parsed_commit parsed;
ParseCommitRecord(XLogRecGetInfo(record), xlrec, &parsed);
xact_redo_commit(&parsed, XLogRecGetXid(record),
record->EndRecPtr, XLogRecGetOrigin(record));
}
else if (info == XLOG_XACT_COMMIT_PREPARED)
{
xl_xact_commit *xlrec = (xl_xact_commit *) XLogRecGetData(record);
xl_xact_parsed_commit parsed;
ParseCommitRecord(XLogRecGetInfo(record), xlrec, &parsed);
xact_redo_commit(&parsed, parsed.twophase_xid,
record->EndRecPtr, XLogRecGetOrigin(record));
/* Delete TwoPhaseState gxact entry and/or 2PC file. */
LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
PrepareRedoRemove(parsed.twophase_xid, false);
LWLockRelease(TwoPhaseStateLock);
}
else if (info == XLOG_XACT_ABORT)
{
xl_xact_abort *xlrec = (xl_xact_abort *) XLogRecGetData(record);
xl_xact_parsed_abort parsed;
ParseAbortRecord(XLogRecGetInfo(record), xlrec, &parsed);
xact_redo_abort(&parsed, XLogRecGetXid(record));
}
else if (info == XLOG_XACT_ABORT_PREPARED)
{
xl_xact_abort *xlrec = (xl_xact_abort *) XLogRecGetData(record);
xl_xact_parsed_abort parsed;
ParseAbortRecord(XLogRecGetInfo(record), xlrec, &parsed);
xact_redo_abort(&parsed, parsed.twophase_xid);
/* Delete TwoPhaseState gxact entry and/or 2PC file. */
LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
PrepareRedoRemove(parsed.twophase_xid, false);
LWLockRelease(TwoPhaseStateLock);
}
else if (info == XLOG_XACT_PREPARE)
{
/*
* Store xid and start/end pointers of the WAL record in TwoPhaseState
* gxact entry.
*/
LWLockAcquire(TwoPhaseStateLock, LW_EXCLUSIVE);
PrepareRedoAdd(XLogRecGetData(record),
record->ReadRecPtr,
record->EndRecPtr,
XLogRecGetOrigin(record));
LWLockRelease(TwoPhaseStateLock);
}
else if (info == XLOG_XACT_DISTRIBUTED_COMMIT)
{
xl_xact_commit *xlrec = (xl_xact_commit *) XLogRecGetData(record);
xl_xact_parsed_commit parsed;
ParseCommitRecord(XLogRecGetInfo(record), xlrec, &parsed);
Assert(parsed.twophase_xid == InvalidTransactionId);
xact_redo_distributed_commit(&parsed, XLogRecGetXid(record),
record->EndRecPtr, XLogRecGetOrigin(record));
}
else if (info == XLOG_XACT_DISTRIBUTED_FORGET)
{
xl_xact_distributed_forget *xlrec = (xl_xact_distributed_forget *) XLogRecGetData(record);
xact_redo_distributed_forget(xlrec, XLogRecGetXid(record));
}
else if (info == XLOG_XACT_ASSIGNMENT)
{
xl_xact_assignment *xlrec = (xl_xact_assignment *) XLogRecGetData(record);
if (standbyState >= STANDBY_INITIALIZED)
ProcArrayApplyXidAssignment(xlrec->xtop,
xlrec->nsubxacts, xlrec->xsub);
}
else
elog(PANIC, "xact_redo: unknown op code %u", info);
}
相关信息
相关文章
greenplumn gp_distributed_log 源码
0
赞
热门推荐
-
2、 - 优质文章
-
3、 gate.io
-
8、 golang
-
9、 openharmony
-
10、 Vue中input框自动聚焦