greenplumn ftsprobe 源码
greenplumn ftsprobe 代码
文件路径：/src/backend/fts/ftsprobe.c
/*-------------------------------------------------------------------------
*
* ftsprobe.c
* Implementation of segment probing interface
*
* Portions Copyright (c) 2006-2011, Greenplum inc
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
*
*
* IDENTIFICATION
* src/backend/fts/ftsprobe.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#ifdef HAVE_SYS_POLL_H
#include <sys/poll.h>
#endif
#include "libpq-fe.h"
#include "libpq-int.h"
#include "access/xact.h"
#include "cdb/cdbfts.h"
#include "cdb/cdbvars.h"
#include "postmaster/fts.h"
#include "postmaster/ftsprobe.h"
#include "postmaster/postmaster.h"
#include "utils/snapmgr.h"
static struct pollfd *PollFds;
static CdbComponentDatabaseInfo *
FtsGetPeerSegment(CdbComponentDatabases *cdbs,
int content, int dbid)
{
int i;
for (i=0; i < cdbs->total_segment_dbs; i++)
{
CdbComponentDatabaseInfo *segInfo = &cdbs->segment_db_info[i];
if (segInfo->config->segindex == content && segInfo->config->dbid != dbid)
{
/* found it */
return segInfo;
}
}
return NULL;
}
static FtsMessageState
nextSuccessState(FtsMessageState state)
{
FtsMessageState result = FTS_PROBE_FAILED; /* to shut up compiler */
switch(state)
{
case FTS_PROBE_SEGMENT:
result = FTS_PROBE_SUCCESS;
break;
case FTS_SYNCREP_OFF_SEGMENT:
result = FTS_SYNCREP_OFF_SUCCESS;
break;
case FTS_PROMOTE_SEGMENT:
result = FTS_PROMOTE_SUCCESS;
break;
case FTS_PROBE_RETRY_WAIT:
case FTS_SYNCREP_OFF_RETRY_WAIT:
case FTS_PROMOTE_RETRY_WAIT:
case FTS_PROBE_SUCCESS:
case FTS_SYNCREP_OFF_SUCCESS:
case FTS_PROMOTE_SUCCESS:
case FTS_PROBE_FAILED:
case FTS_SYNCREP_OFF_FAILED:
case FTS_PROMOTE_FAILED:
case FTS_RESPONSE_PROCESSED:
elog(ERROR, "cannot determine next success state for %d", state);
}
return result;
}
static FtsMessageState
nextFailedState(FtsMessageState state)
{
FtsMessageState result = FTS_PROBE_FAILED; /* to shut up compiler */
switch(state)
{
case FTS_PROBE_SEGMENT:
result = FTS_PROBE_FAILED;
break;
case FTS_SYNCREP_OFF_SEGMENT:
result = FTS_SYNCREP_OFF_FAILED;
break;
case FTS_PROMOTE_SEGMENT:
result = FTS_PROMOTE_FAILED;
break;
case FTS_PROBE_FAILED:
result = FTS_PROBE_FAILED;
break;
case FTS_SYNCREP_OFF_FAILED:
result = FTS_SYNCREP_OFF_FAILED;
break;
case FTS_PROMOTE_FAILED:
result = FTS_PROMOTE_FAILED;
break;
case FTS_PROBE_RETRY_WAIT:
result = FTS_PROBE_FAILED;
break;
case FTS_SYNCREP_OFF_RETRY_WAIT:
result = FTS_SYNCREP_OFF_FAILED;
break;
case FTS_PROMOTE_RETRY_WAIT:
result = FTS_PROMOTE_FAILED;
break;
case FTS_PROBE_SUCCESS:
case FTS_SYNCREP_OFF_SUCCESS:
case FTS_PROMOTE_SUCCESS:
case FTS_RESPONSE_PROCESSED:
elog(ERROR, "cannot determine next failed state for %d", state);
}
return result;
}
static bool
allDone(fts_context *context)
{
bool result = true;
int i;
for (i = 0; i < context->num_pairs && result; i++)
{
/*
* If any segment is not in a final state, return false.
*/
result = (context->perSegInfos[i].state == FTS_RESPONSE_PROCESSED);
}
return result;
}
/*
* Establish async libpq connection to a segment
*/
static bool
ftsConnectStart(fts_segment_info *ftsInfo)
{
char conninfo[1024];
char *hostip;
/*
* No events should be pending on the connection that hasn't started
* yet.
*/
Assert(ftsInfo->poll_revents == 0);
/*
* The segment acting as primary should be the one to receive PROBE or
* SYNCREP_OFF messages.
*/
AssertImply(ftsInfo->state == FTS_PROBE_SEGMENT ||
ftsInfo->state == FTS_SYNCREP_OFF_SEGMENT,
SEGMENT_IS_ACTIVE_PRIMARY(ftsInfo->primary_cdbinfo));
hostip = ftsInfo->primary_cdbinfo->config->hostip;
snprintf(conninfo, 1024, "host=%s port=%d gpconntype=%s",
hostip ? hostip : "", ftsInfo->primary_cdbinfo->config->port,
GPCONN_TYPE_FTS);
ftsInfo->conn = PQconnectStart(conninfo);
if (ftsInfo->conn == NULL)
{
elog(ERROR, "FTS: cannot create libpq connection object, possibly out"
" of memory (content=%d, dbid=%d)",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid);
}
if (ftsInfo->conn->status == CONNECTION_BAD)
{
elog(LOG, "FTS: cannot establish libpq connection to "
"(content=%d, dbid=%d): %s",
ftsInfo->primary_cdbinfo->config->segindex, ftsInfo->primary_cdbinfo->config->dbid,
PQerrorMessage(ftsInfo->conn));
return false;
}
/*
* Connection started, we must wait until the socket becomes ready for
* writing before anything can be written on this socket. Therefore, mark
* the connection to be considered for subsequent poll step.
*/
ftsInfo->poll_events |= POLLOUT;
/*
* Start the timer.
*/
ftsInfo->startTime = (pg_time_t) time(NULL);
return true;
}
/*
* Check if the primary segment is restarting normally by examing the PQ error message.
* It could be that they are in RESET (waiting for the children to exit) or making
* progress in RECOVERY. Note there is no good source of RESET progress indications
* that we could check, so we simply always allow it. Normally RESET should be fast
* and there's a timeout in postmaster to guard against long wait.
*/
static void
checkIfFailedDueToNormalRestart(fts_segment_info *ftsInfo)
{
if (strstr(PQerrorMessage(ftsInfo->conn), _(POSTMASTER_IN_RECOVERY_MSG)) ||
strstr(PQerrorMessage(ftsInfo->conn), _(POSTMASTER_IN_STARTUP_MSG)))
{
XLogRecPtr tmpptr;
char *ptr = strstr(PQerrorMessage(ftsInfo->conn),
_(POSTMASTER_IN_RECOVERY_DETAIL_MSG));
uint32 tmp_xlogid;
uint32 tmp_xrecoff;
if ((ptr == NULL) ||
sscanf(ptr, POSTMASTER_IN_RECOVERY_DETAIL_MSG " %X/%X\n",
&tmp_xlogid, &tmp_xrecoff) != 2)
{
#ifdef USE_ASSERT_CHECKING
elog(ERROR,
#else
elog(LOG,
#endif
"invalid in-recovery message %s "
"(content=%d, dbid=%d) state=%d",
PQerrorMessage(ftsInfo->conn),
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state);
return;
}
tmpptr = ((uint64) tmp_xlogid) << 32 | (uint64) tmp_xrecoff;
/*
* If the xlog record returned from the primary is less than or
* equal to the xlog record we had saved from the last probe
* then we assume that recovery is not making progress. In the
* case of rolling panics on the primary the returned xlog
* location can be less than the recorded xlog location. In
* these cases of rolling panic or recovery hung we want to
* mark the primary as down.
*/
if (tmpptr <= ftsInfo->xlogrecptr)
{
ftsInfo->restart_state = PM_IN_RECOVERY_NOT_MAKING_PROGRESS;
elog(LOG, "FTS: detected segment is in recovery mode and not making progress (content=%d) "
"primary dbid=%d, mirror dbid=%d",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->mirror_cdbinfo->config->dbid);
}
else
{
ftsInfo->restart_state = PM_IN_RECOVERY_MAKING_PROGRESS;
ftsInfo->xlogrecptr = tmpptr;
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS: detected segment is in recovery mode replayed (%X/%X) (content=%d) "
"primary dbid=%d, mirror dbid=%d",
(uint32) (tmpptr >> 32),
(uint32) tmpptr,
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->mirror_cdbinfo->config->dbid);
}
}
else if (strstr(PQerrorMessage(ftsInfo->conn), _(POSTMASTER_IN_RESET_MSG)))
{
ftsInfo->restart_state = PM_IN_RESETTING;
elog(LOG, "FTS: detected segment is in RESET state (content=%d) "
"primary dbid=%d, mirror dbid=%d",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->mirror_cdbinfo->config->dbid);
}
}
/*
* Start a libpq connection for each "per segment" object in context. If the
* connection is already started for an object, advance libpq state machine for
* that object by calling PQconnectPoll(). An established libpq connection
* (authentication complete and ready-for-query received) is identified by: (1)
* state of the "per segment" object is any of FTS_PROBE_SEGMENT,
* FTS_SYNCREP_OFF_SEGMENT, FTS_PROMOTE_SEGMENT and (2) PQconnectPoll() returns
* PGRES_POLLING_OK for the connection.
*
* Upon failure, transition that object to a failed state.
*/
static void
ftsConnect(fts_context *context)
{
int i;
for (i = 0; i < context->num_pairs; i++)
{
fts_segment_info *ftsInfo = &context->perSegInfos[i];
elogif(gp_log_fts == GPVARS_VERBOSITY_DEBUG, LOG,
"FTS: ftsConnect (content=%d, dbid=%d) state=%d, "
"retry_count=%d, conn->status=%d",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
ftsInfo->conn ? ftsInfo->conn->status : -1);
if (ftsInfo->conn && PQstatus(ftsInfo->conn) == CONNECTION_OK)
continue;
switch(ftsInfo->state)
{
case FTS_PROBE_SEGMENT:
case FTS_SYNCREP_OFF_SEGMENT:
case FTS_PROMOTE_SEGMENT:
/*
* We always default to PM_NOT_IN_RESTART. If connect fails, we then check
* the primary's restarting state, so we can skip promoting mirror if it's in
* PM_IN_RESETTING or PM_IN_RECOVERY_MAKING_PROGRESS.
*/
ftsInfo->restart_state = PM_NOT_IN_RESTART;
if (ftsInfo->conn == NULL)
{
AssertImply(ftsInfo->retry_count > 0,
ftsInfo->retry_count <= gp_fts_probe_retries);
if (!ftsConnectStart(ftsInfo))
ftsInfo->state = nextFailedState(ftsInfo->state);
}
else if (ftsInfo->poll_revents & (POLLOUT | POLLIN))
{
switch(PQconnectPoll(ftsInfo->conn))
{
case PGRES_POLLING_OK:
/*
* Response-state is already set and now the
* connection is also ready with authentication
* completed. Next step should now be able to send
* the appropriate FTS message.
*/
elogif(gp_log_fts == GPVARS_VERBOSITY_DEBUG, LOG,
"FTS: established libpq connection "
"(content=%d, dbid=%d) state=%d, "
"retry_count=%d, conn->status=%d",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
ftsInfo->conn->status);
ftsInfo->poll_events = POLLOUT;
break;
case PGRES_POLLING_READING:
/*
* The connection can now be polled for reading and
* if the poll() returns POLLIN in revents, data
* has arrived.
*/
ftsInfo->poll_events |= POLLIN;
break;
case PGRES_POLLING_WRITING:
/*
* The connection can now be polled for writing and
* may be written to, if ready.
*/
ftsInfo->poll_events |= POLLOUT;
break;
case PGRES_POLLING_FAILED:
ftsInfo->state = nextFailedState(ftsInfo->state);
checkIfFailedDueToNormalRestart(ftsInfo);
elog(LOG, "FTS: cannot establish libpq connection "
"(content=%d, dbid=%d): %s, retry_count=%d",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
PQerrorMessage(ftsInfo->conn),
ftsInfo->retry_count);
break;
default:
elog(ERROR, "FTS: invalid response to PQconnectPoll"
" (content=%d, dbid=%d): %s",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
PQerrorMessage(ftsInfo->conn));
break;
}
}
else
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS: ftsConnect (content=%d, dbid=%d) state=%d, "
"retry_count=%d, conn->status=%d pollfd.revents unset",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
ftsInfo->conn ? ftsInfo->conn->status : -1);
break;
case FTS_PROBE_SUCCESS:
case FTS_SYNCREP_OFF_SUCCESS:
case FTS_PROMOTE_SUCCESS:
case FTS_PROBE_FAILED:
case FTS_SYNCREP_OFF_FAILED:
case FTS_PROMOTE_FAILED:
case FTS_PROBE_RETRY_WAIT:
case FTS_SYNCREP_OFF_RETRY_WAIT:
case FTS_PROMOTE_RETRY_WAIT:
case FTS_RESPONSE_PROCESSED:
break;
}
}
}
/*
* Timeout is said to have occurred if greater than gp_fts_probe_timeout
* seconds have elapsed since connection start and a response is not received.
* Segments for which a response is received already are exempted from timeout
* evaluation.
*/
static void
ftsCheckTimeout(fts_segment_info *ftsInfo, pg_time_t now)
{
if (!IsFtsMessageStateSuccess(ftsInfo->state) &&
(int) (now - ftsInfo->startTime) > gp_fts_probe_timeout)
{
elog(LOG,
"FTS timeout detected for (content=%d, dbid=%d) "
"state=%d, retry_count=%d,",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid, ftsInfo->state,
ftsInfo->retry_count);
ftsInfo->state = nextFailedState(ftsInfo->state);
}
}
static void
ftsPoll(fts_context *context)
{
int i;
int nfds=0;
int nready;
for (i = 0; i < context->num_pairs; i++)
{
fts_segment_info *ftsInfo = &context->perSegInfos[i];
if (ftsInfo->poll_events & (POLLIN|POLLOUT))
{
PollFds[nfds].fd = PQsocket(ftsInfo->conn);
PollFds[nfds].events = ftsInfo->poll_events;
PollFds[nfds].revents = 0;
ftsInfo->fd_index = nfds;
nfds++;
}
else
ftsInfo->fd_index = -1; /*
* This socket is not considered for
* polling.
*/
}
if (nfds == 0)
return;
nready = poll(PollFds, nfds, 50);
if (nready < 0)
{
if (errno == EINTR)
{
elogif(gp_log_fts == GPVARS_VERBOSITY_DEBUG, LOG,
"FTS: ftsPoll() interrupted, nfds %d", nfds);
}
else
elog(ERROR, "FTS: ftsPoll() failed: nfds %d, %m", nfds);
}
else if (nready == 0)
{
elogif(gp_log_fts == GPVARS_VERBOSITY_DEBUG, LOG,
"FTS: ftsPoll() timed out, nfds %d", nfds);
}
elogif(gp_log_fts == GPVARS_VERBOSITY_DEBUG, LOG,
"FTS: ftsPoll() found %d out of %d sockets ready",
nready, nfds);
pg_time_t now = (pg_time_t) time(NULL);
/* Record poll() response poll_revents for each "per_segment" object. */
for (i = 0; i < context->num_pairs; i++)
{
fts_segment_info *ftsInfo = &context->perSegInfos[i];
if (ftsInfo->poll_events & (POLLIN|POLLOUT))
{
Assert(PollFds[ftsInfo->fd_index].fd == PQsocket(ftsInfo->conn));
ftsInfo->poll_revents = PollFds[ftsInfo->fd_index].revents;
/*
* Reset poll_events for fds that were found ready. Assume
* that at the most one bit is set in poll_events (POLLIN
* or POLLOUT).
*/
if (ftsInfo->poll_revents & ftsInfo->poll_events)
{
ftsInfo->poll_events = 0;
}
else if (ftsInfo->poll_revents & (POLLHUP | POLLERR))
{
ftsInfo->state = nextFailedState(ftsInfo->state);
elog(LOG,
"FTS poll failed (revents=%d, events=%d) for "
"(content=%d, dbid=%d) state=%d, retry_count=%d, "
"libpq status=%d, asyncStatus=%d",
ftsInfo->poll_revents, ftsInfo->poll_events,
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid, ftsInfo->state,
ftsInfo->retry_count, ftsInfo->conn->status,
ftsInfo->conn->asyncStatus);
}
else if (ftsInfo->poll_revents)
{
ftsInfo->state = nextFailedState(ftsInfo->state);
elog(LOG,
"FTS unexpected events (revents=%d, events=%d) for "
"(content=%d, dbid=%d) state=%d, retry_count=%d, "
"libpq status=%d, asyncStatus=%d",
ftsInfo->poll_revents, ftsInfo->poll_events,
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid, ftsInfo->state,
ftsInfo->retry_count, ftsInfo->conn->status,
ftsInfo->conn->asyncStatus);
}
/* If poll timed-out above, check timeout */
ftsCheckTimeout(ftsInfo, now);
}
}
}
/*
* Send FTS query
*/
static void
ftsSend(fts_context *context)
{
fts_segment_info *ftsInfo;
const char *message_type;
char message[FTS_MSG_MAX_LEN];
int i;
for (i = 0; i < context->num_pairs; i++)
{
ftsInfo = &context->perSegInfos[i];
elogif(gp_log_fts == GPVARS_VERBOSITY_DEBUG, LOG,
"FTS: ftsSend (content=%d, dbid=%d) state=%d, "
"retry_count=%d, conn->asyncStatus=%d",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
ftsInfo->conn ? ftsInfo->conn->asyncStatus : -1);
switch(ftsInfo->state)
{
case FTS_PROBE_SEGMENT:
case FTS_SYNCREP_OFF_SEGMENT:
case FTS_PROMOTE_SEGMENT:
/*
* The libpq connection must be ready for accepting query and
* the socket must be writable.
*/
if (PQstatus(ftsInfo->conn) != CONNECTION_OK ||
ftsInfo->conn->asyncStatus != PGASYNC_IDLE ||
!(ftsInfo->poll_revents & POLLOUT))
break;
if (ftsInfo->state == FTS_PROBE_SEGMENT)
message_type = FTS_MSG_PROBE;
else if (ftsInfo->state == FTS_SYNCREP_OFF_SEGMENT)
message_type = FTS_MSG_SYNCREP_OFF;
else
message_type = FTS_MSG_PROMOTE;
snprintf(message, FTS_MSG_MAX_LEN, FTS_MSG_FORMAT,
message_type,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->primary_cdbinfo->config->segindex);
if (PQsendQuery(ftsInfo->conn, message))
{
/*
* Message sent successfully, mark the socket to be polled
* for reading so we will be ready to read response when it
* arrives.
*/
ftsInfo->poll_events = POLLIN;
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS sent %s to (content=%d, dbid=%d), retry_count=%d",
message, ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid, ftsInfo->retry_count);
}
else
{
elog(LOG,
"FTS: failed to send %s to segment (content=%d, "
"dbid=%d) state=%d, retry_count=%d, "
"conn->asyncStatus=%d %s", message,
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
ftsInfo->conn->asyncStatus,
PQerrorMessage(ftsInfo->conn));
ftsInfo->state = nextFailedState(ftsInfo->state);
}
break;
default:
/* Cannot send messages in any other state. */
break;
}
}
}
/*
* Record FTS handler's response from libpq result into fts_result
*/
static void
probeRecordResponse(fts_segment_info *ftsInfo, PGresult *result)
{
ftsInfo->result.isPrimaryAlive = true;
ftsInfo->result.isMirrorAlive = *PQgetvalue(result, 0,
Anum_fts_message_response_is_mirror_up);
ftsInfo->result.isInSync = *PQgetvalue(result, 0,
Anum_fts_message_response_is_in_sync);
ftsInfo->result.isSyncRepEnabled = *PQgetvalue(result, 0,
Anum_fts_message_response_is_syncrep_enabled);
ftsInfo->result.isRoleMirror = *PQgetvalue(result, 0,
Anum_fts_message_response_is_role_mirror);
ftsInfo->result.retryRequested = *PQgetvalue(result, 0,
Anum_fts_message_response_request_retry);
elogif(gp_log_fts >= GPVARS_VERBOSITY_DEBUG, LOG,
"FTS: segment (content=%d, dbid=%d, role=%c) reported "
"isMirrorUp %d, isInSync %d, isSyncRepEnabled %d, "
"isRoleMirror %d, and retryRequested %d to the prober.",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->primary_cdbinfo->config->role,
ftsInfo->result.isMirrorAlive,
ftsInfo->result.isInSync,
ftsInfo->result.isSyncRepEnabled,
ftsInfo->result.isRoleMirror,
ftsInfo->result.retryRequested);
}
/*
* Receive segment response
*/
static void
ftsReceive(fts_context *context)
{
fts_segment_info *ftsInfo;
PGresult *result = NULL;
int ntuples;
int nfields;
int i;
for (i = 0; i < context->num_pairs; i++)
{
ftsInfo = &context->perSegInfos[i];
elogif(gp_log_fts == GPVARS_VERBOSITY_DEBUG, LOG,
"FTS: ftsReceive (content=%d, dbid=%d) state=%d, "
"retry_count=%d, conn->asyncStatus=%d",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
ftsInfo->conn ? ftsInfo->conn->asyncStatus : -1);
switch(ftsInfo->state)
{
case FTS_PROBE_SEGMENT:
case FTS_SYNCREP_OFF_SEGMENT:
case FTS_PROMOTE_SEGMENT:
/*
* The libpq connection must be established and a message must
* have arrived on the socket.
*/
if (PQstatus(ftsInfo->conn) != CONNECTION_OK ||
!(ftsInfo->poll_revents & POLLIN))
break;
/* Read the response that has arrived. */
if (!PQconsumeInput(ftsInfo->conn))
{
elog(LOG, "FTS: failed to read from (content=%d, dbid=%d)"
" state=%d, retry_count=%d, conn->asyncStatus=%d %s",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
ftsInfo->conn->asyncStatus,
PQerrorMessage(ftsInfo->conn));
ftsInfo->state = nextFailedState(ftsInfo->state);
break;
}
/* Parse the response. */
if (PQisBusy(ftsInfo->conn))
{
/*
* There is not enough data in the buffer.
*/
break;
}
/*
* Response parsed, PQgetResult() should not block for I/O now.
*/
result = PQgetResult(ftsInfo->conn);
if (!result || PQstatus(ftsInfo->conn) == CONNECTION_BAD)
{
elog(LOG, "FTS: error getting results from (content=%d, "
"dbid=%d) state=%d, retry_count=%d, "
"conn->asyncStatus=%d conn->status=%d %s",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
ftsInfo->conn->asyncStatus,
ftsInfo->conn->status,
PQerrorMessage(ftsInfo->conn));
ftsInfo->state = nextFailedState(ftsInfo->state);
break;
}
if (PQresultStatus(result) != PGRES_TUPLES_OK)
{
elog(LOG, "FTS: error response from (content=%d, dbid=%d)"
" state=%d, retry_count=%d, conn->asyncStatus=%d %s",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
ftsInfo->conn->asyncStatus,
PQresultErrorMessage(result));
ftsInfo->state = nextFailedState(ftsInfo->state);
break;
}
ntuples = PQntuples(result);
nfields = PQnfields(result);
if (nfields != Natts_fts_message_response ||
ntuples != FTS_MESSAGE_RESPONSE_NTUPLES)
{
/*
* XXX: Investigate: including conn->asyncStatus generated
* a format string warning at compile time.
*/
elog(LOG, "FTS: invalid response from (content=%d, dbid=%d)"
" state=%d, retry_count=%d, expected %d tuple with "
"%d fields, got %d tuples with %d fields",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid,
ftsInfo->state, ftsInfo->retry_count,
FTS_MESSAGE_RESPONSE_NTUPLES,
Natts_fts_message_response, ntuples, nfields);
ftsInfo->state = nextFailedState(ftsInfo->state);
break;
}
/*
* Result received and parsed successfully. Record it so that
* subsequent step processes it and transitions to next state.
*/
probeRecordResponse(ftsInfo, result);
ftsInfo->state = nextSuccessState(ftsInfo->state);
break;
default:
/* Cannot receive response in any other state. */
break;
}
/*
* Reference to the result should already be stored in
* connection object. If it is not then free explicitly.
*/
if (result && result != ftsInfo->conn->result)
{
PQclear(result);
result = NULL;
}
}
}
static void
retryForFtsFailed(fts_segment_info *ftsInfo, pg_time_t now)
{
if (ftsInfo->retry_count == gp_fts_probe_retries)
{
elog(LOG, "FTS max (%d) retries exhausted "
"(content=%d, dbid=%d) state=%d",
ftsInfo->retry_count,
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid, ftsInfo->state);
return;
}
ftsInfo->retry_count++;
if (ftsInfo->state == FTS_PROBE_SUCCESS ||
ftsInfo->state == FTS_PROBE_FAILED)
ftsInfo->state = FTS_PROBE_RETRY_WAIT;
else if (ftsInfo->state == FTS_SYNCREP_OFF_FAILED)
ftsInfo->state = FTS_SYNCREP_OFF_RETRY_WAIT;
else
ftsInfo->state = FTS_PROMOTE_RETRY_WAIT;
ftsInfo->retryStartTime = now;
elogif(gp_log_fts == GPVARS_VERBOSITY_DEBUG, LOG,
"FTS initialized retry start time to now "
"(content=%d, dbid=%d) state=%d",
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid, ftsInfo->state);
PQfinish(ftsInfo->conn);
ftsInfo->conn = NULL;
ftsInfo->poll_events = ftsInfo->poll_revents = 0;
/* Reset result before next attempt. */
memset(&ftsInfo->result, 0, sizeof(fts_result));
}
/*
* If retry attempts are available, transition the segments to the start state
* corresponding to their failure state. If retries have exhausted, leave the
* segment in the failure state.
*/
static void
processRetry(fts_context *context)
{
fts_segment_info *ftsInfo;
int i;
pg_time_t now = (pg_time_t) time(NULL);
for (i = 0; i < context->num_pairs; i++)
{
ftsInfo = &context->perSegInfos[i];
switch(ftsInfo->state)
{
case FTS_PROBE_SUCCESS:
/*
* Purpose of retryRequested flag is to avoid considering
* mirror as down prematurely. If mirror is already marked
* down in configuration, there is no need to retry.
*/
if (!(ftsInfo->result.retryRequested &&
SEGMENT_IS_ALIVE(ftsInfo->mirror_cdbinfo)))
break;
/* else, fallthrough */
case FTS_PROBE_FAILED:
case FTS_SYNCREP_OFF_FAILED:
case FTS_PROMOTE_FAILED:
retryForFtsFailed(ftsInfo, now);
break;
case FTS_PROBE_RETRY_WAIT:
case FTS_SYNCREP_OFF_RETRY_WAIT:
case FTS_PROMOTE_RETRY_WAIT:
/* Wait for 1 second before making another attempt. */
if ((int) (now - ftsInfo->retryStartTime) < 1)
break;
/*
* We have remained in retry state for over a second, it's time
* to make another attempt.
*/
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS retrying attempt %d (content=%d, dbid=%d) "
"state=%d", ftsInfo->retry_count,
ftsInfo->primary_cdbinfo->config->segindex,
ftsInfo->primary_cdbinfo->config->dbid, ftsInfo->state);
if (ftsInfo->state == FTS_PROBE_RETRY_WAIT)
ftsInfo->state = FTS_PROBE_SEGMENT;
else if (ftsInfo->state == FTS_SYNCREP_OFF_RETRY_WAIT)
ftsInfo->state = FTS_SYNCREP_OFF_SEGMENT;
else
ftsInfo->state = FTS_PROMOTE_SEGMENT;
break;
default:
break;
}
}
}
/*
* Return true for segments whose response is ready to be processed. Segments
* whose response is already processed should have response->conn set to NULL.
*/
static bool
ftsResponseReady(fts_segment_info *ftsInfo)
{
return (IsFtsMessageStateSuccess(ftsInfo->state) ||
IsFtsMessageStateFailed(ftsInfo->state));
}
static bool
updateConfiguration(CdbComponentDatabaseInfo *primary,
CdbComponentDatabaseInfo *mirror,
char newPrimaryRole, char newMirrorRole,
bool IsInSync, bool IsPrimaryAlive, bool IsMirrorAlive)
{
bool UpdatePrimary = (IsPrimaryAlive != SEGMENT_IS_ALIVE(primary));
bool UpdateMirror = (IsMirrorAlive != SEGMENT_IS_ALIVE(mirror));
/*
* If probe response state is different from current state in
* configuration, update both primary and mirror.
*/
if (IsInSync != SEGMENT_IS_IN_SYNC(primary))
UpdatePrimary = UpdateMirror = true;
/*
* A mirror being promoted must be already in-sync in configuration.
* Update to the configuration must include mode as not-in-sync and primary
* status as down.
*/
AssertImply(newPrimaryRole == GP_SEGMENT_CONFIGURATION_ROLE_MIRROR,
SEGMENT_IS_IN_SYNC(mirror) && !IsInSync && !IsPrimaryAlive);
/*
* Primary and mirror should always have the same mode in configuration,
* either both reflecting in-sync or not in-sync.
*/
Assert(primary->config->mode == mirror->config->mode);
bool UpdateNeeded = UpdatePrimary || UpdateMirror;
/*
* Commit/abort transaction below will destroy
* CurrentResourceOwner. We need it for catalog reads.
*/
ResourceOwner save = CurrentResourceOwner;
if (UpdateNeeded)
{
StartTransactionCommand();
GetTransactionSnapshot();
if (UpdatePrimary)
probeWalRepUpdateConfig(primary->config->dbid, primary->config->segindex,
newPrimaryRole, IsPrimaryAlive,
IsInSync);
if (UpdateMirror)
probeWalRepUpdateConfig(mirror->config->dbid, mirror->config->segindex,
newMirrorRole, IsMirrorAlive,
IsInSync);
CommitTransactionCommand();
CurrentResourceOwner = save;
/*
* Update the status to in-memory variable as well used by
* dispatcher, now that changes has been persisted to catalog.
*/
Assert(ftsProbeInfo);
if (IsPrimaryAlive)
FTS_STATUS_SET_UP(ftsProbeInfo->status[primary->config->dbid]);
else
FTS_STATUS_SET_DOWN(ftsProbeInfo->status[primary->config->dbid]);
if (IsMirrorAlive)
FTS_STATUS_SET_UP(ftsProbeInfo->status[mirror->config->dbid]);
else
FTS_STATUS_SET_DOWN(ftsProbeInfo->status[mirror->config->dbid]);
}
return UpdateNeeded;
}
/*
* Process responses from primary segments:
* (a) Transition internal state so that segments can be messaged subsequently
* (e.g. promotion and turning off syncrep).
* (b) Update gp_segment_configuration catalog table, if needed.
*/
static bool
processResponse(fts_context *context)
{
bool is_updated = false;
for (int response_index = 0;
response_index < context->num_pairs && FtsIsActive();
response_index ++)
{
fts_segment_info *ftsInfo = &(context->perSegInfos[response_index]);
/*
* Consider segments that are in final state (success / failure) and
* that are not already processed.
*/
if (!ftsResponseReady(ftsInfo))
continue;
/* All retries must have exhausted before a failure is processed. */
AssertImply(IsFtsMessageStateFailed(ftsInfo->state),
ftsInfo->retry_count == gp_fts_probe_retries);
CdbComponentDatabaseInfo *primary = ftsInfo->primary_cdbinfo;
CdbComponentDatabaseInfo *mirror = ftsInfo->mirror_cdbinfo;
bool IsPrimaryAlive = ftsInfo->result.isPrimaryAlive;
/* Trust a response from primary only if it's alive. */
bool IsMirrorAlive = IsPrimaryAlive ?
ftsInfo->result.isMirrorAlive : SEGMENT_IS_ALIVE(mirror);
bool IsInSync = IsPrimaryAlive ?
ftsInfo->result.isInSync : false;
/* If primary and mirror are in sync, then both have to be ALIVE. */
AssertImply(IsInSync, IsPrimaryAlive && IsMirrorAlive);
/* Primary must enable syncrep as long as it thinks mirror is alive. */
AssertImply(IsMirrorAlive && IsPrimaryAlive,
ftsInfo->result.isSyncRepEnabled);
switch(ftsInfo->state)
{
case FTS_PROBE_SUCCESS:
Assert(IsPrimaryAlive);
if (ftsInfo->result.isSyncRepEnabled && !IsMirrorAlive)
{
if (!ftsInfo->result.retryRequested)
{
/*
* Primaries that have syncrep enabled continue to block
* commits until FTS update the mirror status as down.
*/
is_updated |= updateConfiguration(
primary, mirror,
GP_SEGMENT_CONFIGURATION_ROLE_PRIMARY,
GP_SEGMENT_CONFIGURATION_ROLE_MIRROR,
IsInSync, IsPrimaryAlive, IsMirrorAlive);
/*
* If mirror was marked up in configuration, it must have
* been marked down by updateConfiguration().
*/
AssertImply(SEGMENT_IS_ALIVE(mirror), is_updated);
/*
* Now that the configuration is updated, FTS must notify
* the primaries to unblock commits by sending syncrep off
* message.
*/
ftsInfo->state = FTS_SYNCREP_OFF_SEGMENT;
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS turning syncrep off on (content=%d, dbid=%d)",
primary->config->segindex, primary->config->dbid);
}
else
{
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS skipping mirror down update for (content=%d) as retryRequested",
primary->config->segindex);
ftsInfo->state = FTS_RESPONSE_PROCESSED;
}
}
else if (ftsInfo->result.isRoleMirror)
{
/*
* A promote message sent previously didn't make it to the
* mirror. Catalog must have been updated before sending
* the previous promote message.
*/
Assert(!IsMirrorAlive);
Assert(!SEGMENT_IS_ALIVE(mirror));
Assert(SEGMENT_IS_NOT_INSYNC(mirror));
Assert(SEGMENT_IS_NOT_INSYNC(primary));
Assert(!ftsInfo->result.isSyncRepEnabled);
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS resending promote request to (content=%d,"
" dbid=%d)", primary->config->segindex, primary->config->dbid);
ftsInfo->state = FTS_PROMOTE_SEGMENT;
}
else
{
/*
* No subsequent state transition needed, update catalog if
* necessary. The cases are mirror status found to change
* from down to up, mode found to change from not in-sync
* to in-sync or syncrep found to change from off to on.
*/
is_updated |= updateConfiguration(
primary, mirror,
GP_SEGMENT_CONFIGURATION_ROLE_PRIMARY,
GP_SEGMENT_CONFIGURATION_ROLE_MIRROR,
IsInSync, IsPrimaryAlive, IsMirrorAlive);
ftsInfo->state = FTS_RESPONSE_PROCESSED;
}
break;
case FTS_PROBE_FAILED:
/* Primary is down */
/* If primary is in resetting or making progress in recovery, do not mark it down and promote mirror */
if (ftsInfo->restart_state == PM_IN_RESETTING)
{
Assert(strstr(PQerrorMessage(ftsInfo->conn), _(POSTMASTER_IN_RESET_MSG)));
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS: detected segment is in resetting mode "
"(content=%d) primary dbid=%d, mirror dbid=%d",
primary->config->segindex, primary->config->dbid, mirror->config->dbid);
ftsInfo->state = FTS_RESPONSE_PROCESSED;
break;
}
else if (ftsInfo->restart_state == PM_IN_RECOVERY_MAKING_PROGRESS)
{
Assert(strstr(PQerrorMessage(ftsInfo->conn), _(POSTMASTER_IN_RECOVERY_MSG)) ||
strstr(PQerrorMessage(ftsInfo->conn), _(POSTMASTER_IN_STARTUP_MSG)));
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS: detected segment is in recovery mode and making "
"progress (content=%d) primary dbid=%d, mirror dbid=%d",
primary->config->segindex, primary->config->dbid, mirror->config->dbid);
ftsInfo->state = FTS_RESPONSE_PROCESSED;
break;
}
Assert(!IsPrimaryAlive);
/* See if mirror can be promoted. */
if (SEGMENT_IS_IN_SYNC(mirror))
{
/*
* Primary and mirror must have been recorded as in-sync
* before the probe.
*/
Assert(SEGMENT_IS_IN_SYNC(primary));
/*
* Flip the roles and mark the failed primary as down in
* FTS configuration before sending promote message.
* Dispatcher should no longer consider the failed primary
* for gang creation, FTS should no longer probe the failed
* primary.
*/
is_updated |= updateConfiguration(
primary, mirror,
GP_SEGMENT_CONFIGURATION_ROLE_MIRROR, /* newPrimaryRole */
GP_SEGMENT_CONFIGURATION_ROLE_PRIMARY, /* newMirrorRole */
IsInSync, IsPrimaryAlive, IsMirrorAlive);
Assert(is_updated);
/*
* Swap the primary and mirror references so that the
* mirror will be promoted in subsequent connect, poll,
* send, receive steps.
*/
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS promoting mirror (content=%d, dbid=%d) "
"to be the new primary",
mirror->config->segindex, mirror->config->dbid);
ftsInfo->state = FTS_PROMOTE_SEGMENT;
ftsInfo->primary_cdbinfo = mirror;
ftsInfo->mirror_cdbinfo = primary;
}
else
{
/*
* Only log here, will handle it later, having an "ERROR"
* keyword here for customer convenience
*/
elog(WARNING, "ERROR: FTS double fault detected (content=%d) "
"primary dbid=%d, mirror dbid=%d",
primary->config->segindex, primary->config->dbid, mirror->config->dbid);
ftsInfo->state = FTS_RESPONSE_PROCESSED;
}
break;
case FTS_SYNCREP_OFF_FAILED:
/*
* Another attempt to turn off syncrep will be made in the next
* probe cycle. Until then, leave the transactions waiting for
* syncrep. A worse alternative is to PANIC.
*/
elog(WARNING, "FTS failed to turn off syncrep on (content=%d,"
" dbid=%d)", primary->config->segindex, primary->config->dbid);
ftsInfo->state = FTS_RESPONSE_PROCESSED;
break;
case FTS_PROMOTE_FAILED:
/*
* Only log here, will handle it later, having an "ERROR"
* keyword here for customer convenience
*/
elog(WARNING, "ERROR: FTS double fault detected (content=%d) "
"primary dbid=%d, mirror dbid=%d",
primary->config->segindex, primary->config->dbid, mirror->config->dbid);
ftsInfo->state = FTS_RESPONSE_PROCESSED;
break;
case FTS_PROMOTE_SUCCESS:
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS mirror (content=%d, dbid=%d) promotion "
"triggered successfully",
primary->config->segindex, primary->config->dbid);
ftsInfo->state = FTS_RESPONSE_PROCESSED;
break;
case FTS_SYNCREP_OFF_SUCCESS:
elogif(gp_log_fts >= GPVARS_VERBOSITY_VERBOSE, LOG,
"FTS primary (content=%d, dbid=%d) notified to turn "
"syncrep off", primary->config->segindex, primary->config->dbid);
ftsInfo->state = FTS_RESPONSE_PROCESSED;
break;
default:
elog(ERROR, "FTS invalid internal state %d for (content=%d)"
"primary dbid=%d, mirror dbid=%d", ftsInfo->state,
primary->config->segindex, primary->config->dbid, mirror->config->dbid);
break;
}
/* Close connection and reset result for next message, if any. */
memset(&ftsInfo->result, 0, sizeof(fts_result));
PQfinish(ftsInfo->conn);
ftsInfo->conn = NULL;
ftsInfo->poll_events = ftsInfo->poll_revents = 0;
ftsInfo->retry_count = 0;
}
return is_updated;
}
#ifdef USE_ASSERT_CHECKING
static bool
FtsIsSegmentAlive(CdbComponentDatabaseInfo *segInfo)
{
if (SEGMENT_IS_ACTIVE_MIRROR(segInfo) && SEGMENT_IS_ALIVE(segInfo))
return true;
if (SEGMENT_IS_ACTIVE_PRIMARY(segInfo))
return true;
return false;
}
#endif
/*
* Initialize context before a probe cycle based on cluster configuration in
* cdbs.
*/
static void
FtsWalRepInitProbeContext(CdbComponentDatabases *cdbs, fts_context *context)
{
context->num_pairs = cdbs->total_segments;
context->perSegInfos = (fts_segment_info *) palloc0(
context->num_pairs * sizeof(fts_segment_info));
int fts_index = 0;
int cdb_index = 0;
for(; cdb_index < cdbs->total_segment_dbs; cdb_index++)
{
CdbComponentDatabaseInfo *primary = &(cdbs->segment_db_info[cdb_index]);
if (!SEGMENT_IS_ACTIVE_PRIMARY(primary))
continue;
CdbComponentDatabaseInfo *mirror = FtsGetPeerSegment(cdbs,
primary->config->segindex,
primary->config->dbid);
/*
* If there is no mirror under this primary, no need to probe.
*/
if (!mirror)
{
context->num_pairs--;
continue;
}
/* primary in catalog will NEVER be marked down. */
Assert(FtsIsSegmentAlive(primary));
fts_segment_info *ftsInfo = &(context->perSegInfos[fts_index]);
/*
* Initialize the response object. Response from a segment will be
* processed only if ftsInfo->state is one of SUCCESS states. If a
* failure is encountered in messaging a segment, its response will not
* be processed.
*/
ftsInfo->result.isPrimaryAlive = false;
ftsInfo->result.isMirrorAlive = false;
ftsInfo->result.isInSync = false;
ftsInfo->result.isSyncRepEnabled = false;
ftsInfo->result.retryRequested = false;
ftsInfo->result.isRoleMirror = false;
ftsInfo->result.dbid = primary->config->dbid;
ftsInfo->state = FTS_PROBE_SEGMENT;
ftsInfo->restart_state = PM_NOT_IN_RESTART;
ftsInfo->xlogrecptr = InvalidXLogRecPtr;
ftsInfo->primary_cdbinfo = primary;
ftsInfo->mirror_cdbinfo = mirror;
Assert(fts_index < context->num_pairs);
fts_index ++;
}
}
static void
InitPollFds(size_t size)
{
PollFds = (struct pollfd *) palloc0(size * sizeof(struct pollfd));
}
bool
FtsWalRepMessageSegments(CdbComponentDatabases *cdbs)
{
bool is_updated = false;
fts_context context;
FtsWalRepInitProbeContext(cdbs, &context);
InitPollFds(cdbs->total_segments);
while (!allDone(&context) && FtsIsActive())
{
ftsConnect(&context);
ftsPoll(&context);
ftsSend(&context);
ftsReceive(&context);
processRetry(&context);
is_updated |= processResponse(&context);
}
int i;
if (!FtsIsActive())
{
for (i = 0; i < context.num_pairs; i++)
{
if (context.perSegInfos[i].conn)
{
PQfinish(context.perSegInfos[i].conn);
context.perSegInfos[i].conn = NULL;
}
}
}
#ifdef USE_ASSERT_CHECKING
/*
* At the end of probe cycle, there shouldn't be any active libpq
* connections.
*/
for (i = 0; i < context.num_pairs; i++)
{
if (context.perSegInfos[i].conn != NULL)
elog(ERROR,
"FTS libpq connection left open (content=%d, dbid=%d)"
" state=%d, retry_count=%d, conn->status=%d",
context.perSegInfos[i].primary_cdbinfo->config->segindex,
context.perSegInfos[i].primary_cdbinfo->config->dbid,
context.perSegInfos[i].state,
context.perSegInfos[i].retry_count,
context.perSegInfos[i].conn->status);
}
#endif
pfree(context.perSegInfos);
pfree(PollFds);
return is_updated;
}
/* EOF */
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