greenplumn nodeAgg 源码
greenplumn nodeAgg 代码
文件路径：/src/backend/executor/nodeAgg.c
/*-------------------------------------------------------------------------
*
* nodeAgg.c
* Routines to handle aggregate nodes.
*
* ExecAgg normally evaluates each aggregate in the following steps:
*
* transvalue = initcond
* foreach input_tuple do
* transvalue = transfunc(transvalue, input_value(s))
* result = finalfunc(transvalue, direct_argument(s))
*
* If a finalfunc is not supplied then the result is just the ending
* value of transvalue.
*
* Other behaviors can be selected by the "aggsplit" mode, which exists
* to support partial aggregation. It is possible to:
* * Skip running the finalfunc, so that the output is always the
* final transvalue state.
* * Substitute the combinefunc for the transfunc, so that transvalue
* states (propagated up from a child partial-aggregation step) are merged
* rather than processing raw input rows. (The statements below about
* the transfunc apply equally to the combinefunc, when it's selected.)
* * Apply the serializefunc to the output values (this only makes sense
* when skipping the finalfunc, since the serializefunc works on the
* transvalue data type).
* * Apply the deserializefunc to the input values (this only makes sense
* when using the combinefunc, for similar reasons).
* It is the planner's responsibility to connect up Agg nodes using these
* alternate behaviors in a way that makes sense, with partial aggregation
* results being fed to nodes that expect them.
*
* If a normal aggregate call specifies DISTINCT or ORDER BY, we sort the
* input tuples and eliminate duplicates (if required) before performing
* the above-depicted process. (However, we don't do that for ordered-set
* aggregates; their "ORDER BY" inputs are ordinary aggregate arguments
* so far as this module is concerned.) Note that partial aggregation
* is not supported in these cases, since we couldn't ensure global
* ordering or distinctness of the inputs.
*
* If transfunc is marked "strict" in pg_proc and initcond is NULL,
* then the first non-NULL input_value is assigned directly to transvalue,
* and transfunc isn't applied until the second non-NULL input_value.
* The agg's first input type and transtype must be the same in this case!
*
* If transfunc is marked "strict" then NULL input_values are skipped,
* keeping the previous transvalue. If transfunc is not strict then it
* is called for every input tuple and must deal with NULL initcond
* or NULL input_values for itself.
*
* If finalfunc is marked "strict" then it is not called when the
* ending transvalue is NULL, instead a NULL result is created
* automatically (this is just the usual handling of strict functions,
* of course). A non-strict finalfunc can make its own choice of
* what to return for a NULL ending transvalue.
*
* Ordered-set aggregates are treated specially in one other way: we
* evaluate any "direct" arguments and pass them to the finalfunc along
* with the transition value.
*
* A finalfunc can have additional arguments beyond the transvalue and
* any "direct" arguments, corresponding to the input arguments of the
* aggregate. These are always just passed as NULL. Such arguments may be
* needed to allow resolution of a polymorphic aggregate's result type.
*
* We compute aggregate input expressions and run the transition functions
* in a temporary econtext (aggstate->tmpcontext). This is reset at least
* once per input tuple, so when the transvalue datatype is
* pass-by-reference, we have to be careful to copy it into a longer-lived
* memory context, and free the prior value to avoid memory leakage. We
* store transvalues in another set of econtexts, aggstate->aggcontexts
* (one per grouping set, see below), which are also used for the hashtable
* structures in AGG_HASHED mode. These econtexts are rescanned, not just
* reset, at group boundaries so that aggregate transition functions can
* register shutdown callbacks via AggRegisterCallback.
*
* The node's regular econtext (aggstate->ss.ps.ps_ExprContext) is used to
* run finalize functions and compute the output tuple; this context can be
* reset once per output tuple.
*
* The executor's AggState node is passed as the fmgr "context" value in
* all transfunc and finalfunc calls. It is not recommended that the
* transition functions look at the AggState node directly, but they can
* use AggCheckCallContext() to verify that they are being called by
* nodeAgg.c (and not as ordinary SQL functions). The main reason a
* transition function might want to know this is so that it can avoid
* palloc'ing a fixed-size pass-by-ref transition value on every call:
* it can instead just scribble on and return its left input. Ordinarily
* it is completely forbidden for functions to modify pass-by-ref inputs,
* but in the aggregate case we know the left input is either the initial
* transition value or a previous function result, and in either case its
* value need not be preserved. See int8inc() for an example. Notice that
* the EEOP_AGG_PLAIN_TRANS step is coded to avoid a data copy step when
* the previous transition value pointer is returned. It is also possible
* to avoid repeated data copying when the transition value is an expanded
* object: to do that, the transition function must take care to return
* an expanded object that is in a child context of the memory context
* returned by AggCheckCallContext(). Also, some transition functions want
* to store working state in addition to the nominal transition value; they
* can use the memory context returned by AggCheckCallContext() to do that.
*
* Note: AggCheckCallContext() is available as of PostgreSQL 9.0. The
* AggState is available as context in earlier releases (back to 8.1),
* but direct examination of the node is needed to use it before 9.0.
*
* As of 9.4, aggregate transition functions can also use AggGetAggref()
* to get hold of the Aggref expression node for their aggregate call.
* This is mainly intended for ordered-set aggregates, which are not
* supported as window functions. (A regular aggregate function would
* need some fallback logic to use this, since there's no Aggref node
* for a window function.)
*
* Grouping sets:
*
* A list of grouping sets which is structurally equivalent to a ROLLUP
* clause (e.g. (a,b,c), (a,b), (a)) can be processed in a single pass over
* ordered data. We do this by keeping a separate set of transition values
* for each grouping set being concurrently processed; for each input tuple
* we update them all, and on group boundaries we reset those states
* (starting at the front of the list) whose grouping values have changed
* (the list of grouping sets is ordered from most specific to least
* specific).
*
* Where more complex grouping sets are used, we break them down into
* "phases", where each phase has a different sort order (except phase 0
* which is reserved for hashing). During each phase but the last, the
* input tuples are additionally stored in a tuplesort which is keyed to the
* next phase's sort order; during each phase but the first, the input
* tuples are drawn from the previously sorted data. (The sorting of the
* data for the first phase is handled by the planner, as it might be
* satisfied by underlying nodes.)
*
* Hashing can be mixed with sorted grouping. To do this, we have an
* AGG_MIXED strategy that populates the hashtables during the first sorted
* phase, and switches to reading them out after completing all sort phases.
* We can also support AGG_HASHED with multiple hash tables and no sorting
* at all.
*
* From the perspective of aggregate transition and final functions, the
* only issue regarding grouping sets is this: a single call site (flinfo)
* of an aggregate function may be used for updating several different
* transition values in turn. So the function must not cache in the flinfo
* anything which logically belongs as part of the transition value (most
* importantly, the memory context in which the transition value exists).
* The support API functions (AggCheckCallContext, AggRegisterCallback) are
* sensitive to the grouping set for which the aggregate function is
* currently being called.
*
* Plan structure:
*
* What we get from the planner is actually one "real" Agg node which is
* part of the plan tree proper, but which optionally has an additional list
* of Agg nodes hung off the side via the "chain" field. This is because an
* Agg node happens to be a convenient representation of all the data we
* need for grouping sets.
*
* For many purposes, we treat the "real" node as if it were just the first
* node in the chain. The chain must be ordered such that hashed entries
* come before sorted/plain entries; the real node is marked AGG_MIXED if
* there are both types present (in which case the real node describes one
* of the hashed groupings, other AGG_HASHED nodes may optionally follow in
* the chain, followed in turn by AGG_SORTED or (one) AGG_PLAIN node). If
* the real node is marked AGG_HASHED or AGG_SORTED, then all the chained
* nodes must be of the same type; if it is AGG_PLAIN, there can be no
* chained nodes.
*
* We collect all hashed nodes into a single "phase", numbered 0, and create
* a sorted phase (numbered 1..n) for each AGG_SORTED or AGG_PLAIN node.
* Phase 0 is allocated even if there are no hashes, but remains unused in
* that case.
*
* AGG_HASHED nodes actually refer to only a single grouping set each,
* because for each hashed grouping we need a separate grpColIdx and
* numGroups estimate. AGG_SORTED nodes represent a "rollup", a list of
* grouping sets that share a sort order. Each AGG_SORTED node other than
* the first one has an associated Sort node which describes the sort order
* to be used; the first sorted node takes its input from the outer subtree,
* which the planner has already arranged to provide ordered data.
*
* Memory and ExprContext usage:
*
* Because we're accumulating aggregate values across input rows, we need to
* use more memory contexts than just simple input/output tuple contexts.
* In fact, for a rollup, we need a separate context for each grouping set
* so that we can reset the inner (finer-grained) aggregates on their group
* boundaries while continuing to accumulate values for outer
* (coarser-grained) groupings. On top of this, we might be simultaneously
* populating hashtables; however, we only need one context for all the
* hashtables.
*
* So we create an array, aggcontexts, with an ExprContext for each grouping
* set in the largest rollup that we're going to process, and use the
* per-tuple memory context of those ExprContexts to store the aggregate
* transition values. hashcontext is the single context created to support
* all hash tables.
*
* Spilling To Disk
*
* When performing hash aggregation, if the hash table memory exceeds the
* limit (see hash_agg_check_limits()), we enter "spill mode". In spill
* mode, we advance the transition states only for groups already in the
* hash table. For tuples that would need to create a new hash table
* entries (and initialize new transition states), we instead spill them to
* disk to be processed later. The tuples are spilled in a partitioned
* manner, so that subsequent batches are smaller and less likely to exceed
* work_mem (if a batch does exceed work_mem, it must be spilled
* recursively).
*
* Spilled data is written to logical tapes. These provide better control
* over memory usage, disk space, and the number of files than if we were
* to use a BufFile for each spill.
*
* Note that it's possible for transition states to start small but then
* grow very large; for instance in the case of ARRAY_AGG. In such cases,
* it's still possible to significantly exceed work_mem. We try to avoid
* this situation by estimating what will fit in the available memory, and
* imposing a limit on the number of groups separately from the amount of
* memory consumed.
*
* Transition / Combine function invocation:
*
* For performance reasons transition functions, including combine
* functions, aren't invoked one-by-one from nodeAgg.c after computing
* arguments using the expression evaluation engine. Instead
* ExecBuildAggTrans() builds one large expression that does both argument
* evaluation and transition function invocation. That avoids performance
* issues due to repeated uses of expression evaluation, complications due
* to filter expressions having to be evaluated early, and allows to JIT
* the entire expression into one native function.
*
* GPDB: Note that statement_mem is used to decide the operator memory
* instead of the work_mem, but to keep minimal change with postgres we keep
* the word "work_mem" in comments.
*
* Portions Copyright (c) 2007-2008, Greenplum inc
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/executor/nodeAgg.c
*
*-------------------------------------------------------------------------
*/
/*
* GPDB_12_MERGE_FIXME: we lost the "streaming bottom" feature in the merge.
*
* And the detailed cdb executor instruments to print by explain.
*
* They were in execHHashagg.c
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_aggregate.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "executor/execExpr.h"
#include "executor/executor.h"
#include "executor/nodeAgg.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/optimizer.h"
#include "parser/parse_agg.h"
#include "parser/parse_coerce.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/dynahash.h"
#include "utils/expandeddatum.h"
#include "utils/faultinjector.h"
#include "utils/logtape.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/syscache.h"
#include "utils/tuplesort.h"
#include "utils/datum.h"
#include "cdb/cdbexplain.h"
#include "lib/stringinfo.h" /* StringInfo */
#include "optimizer/walkers.h"
/*
* Control how many partitions are created when spilling HashAgg to
* disk.
*
* HASHAGG_PARTITION_FACTOR is multiplied by the estimated number of
* partitions needed such that each partition will fit in memory. The factor
* is set higher than one because there's not a high cost to having a few too
* many partitions, and it makes it less likely that a partition will need to
* be spilled recursively. Another benefit of having more, smaller partitions
* is that small hash tables may perform better than large ones due to memory
* caching effects.
*
* We also specify a min and max number of partitions per spill. Too few might
* mean a lot of wasted I/O from repeated spilling of the same tuples. Too
* many will result in lots of memory wasted buffering the spill files (which
* could instead be spent on a larger hash table).
*/
#define HASHAGG_PARTITION_FACTOR 1.50
#define HASHAGG_MIN_PARTITIONS 4
#define HASHAGG_MAX_PARTITIONS 1024
/*
* For reading from tapes, the buffer size must be a multiple of
* BLCKSZ. Larger values help when reading from multiple tapes concurrently,
* but that doesn't happen in HashAgg, so we simply use BLCKSZ. Writing to a
* tape always uses a buffer of size BLCKSZ.
*/
#define HASHAGG_READ_BUFFER_SIZE BLCKSZ
#define HASHAGG_WRITE_BUFFER_SIZE BLCKSZ
/*
* Estimate chunk overhead as a constant 16 bytes. XXX: should this be
* improved?
*/
#define CHUNKHDRSZ 16
/*
* Track all tapes needed for a HashAgg that spills. We don't know the maximum
* number of tapes needed at the start of the algorithm (because it can
* recurse), so one tape set is allocated and extended as needed for new
* tapes. When a particular tape is already read, rewind it for write mode and
* put it in the free list.
*
* Tapes' buffers can take up substantial memory when many tapes are open at
* once. We only need one tape open at a time in read mode (using a buffer
* that's a multiple of BLCKSZ); but we need one tape open in write mode (each
* requiring a buffer of size BLCKSZ) for each partition.
*/
typedef struct HashTapeInfo
{
LogicalTapeSet *tapeset;
int ntapes;
int *freetapes;
int nfreetapes;
int freetapes_alloc;
} HashTapeInfo;
/*
* Represents partitioned spill data for a single hashtable. Contains the
* necessary information to route tuples to the correct partition, and to
* transform the spilled data into new batches.
*
* The high bits are used for partition selection (when recursing, we ignore
* the bits that have already been used for partition selection at an earlier
* level).
*/
typedef struct HashAggSpill
{
LogicalTapeSet *tapeset; /* borrowed reference to tape set */
int npartitions; /* number of partitions */
int *partitions; /* spill partition tape numbers */
int64 *ntuples; /* number of tuples in each partition */
uint32 mask; /* mask to find partition from hash value */
int shift; /* after masking, shift by this amount */
} HashAggSpill;
/*
* Represents work to be done for one pass of hash aggregation (with only one
* grouping set).
*
* Also tracks the bits of the hash already used for partition selection by
* earlier iterations, so that this batch can use new bits. If all bits have
* already been used, no partitioning will be done (any spilled data will go
* to a single output tape).
*/
typedef struct HashAggBatch
{
int setno; /* grouping set */
int used_bits; /* number of bits of hash already used */
LogicalTapeSet *tapeset; /* borrowed reference to tape set */
int input_tapenum; /* input partition tape */
int64 input_tuples; /* number of tuples in this batch */
} HashAggBatch;
static void select_current_set(AggState *aggstate, int setno, bool is_hash);
static void initialize_phase(AggState *aggstate, int newphase);
static TupleTableSlot *fetch_input_tuple(AggState *aggstate);
static void initialize_aggregates(AggState *aggstate,
AggStatePerGroup *pergroups,
int numReset);
static void advance_transition_function(AggState *aggstate,
AggStatePerTrans pertrans,
AggStatePerGroup pergroupstate);
static void advance_aggregates(AggState *aggstate);
static void process_ordered_aggregate_single(AggState *aggstate,
AggStatePerTrans pertrans,
AggStatePerGroup pergroupstate);
static void process_ordered_aggregate_multi(AggState *aggstate,
AggStatePerTrans pertrans,
AggStatePerGroup pergroupstate);
static void finalize_aggregate(AggState *aggstate,
AggStatePerAgg peragg,
AggStatePerGroup pergroupstate,
Datum *resultVal, bool *resultIsNull);
static void finalize_partialaggregate(AggState *aggstate,
AggStatePerAgg peragg,
AggStatePerGroup pergroupstate,
Datum *resultVal, bool *resultIsNull);
static void prepare_hash_slot(AggState *aggstate);
static void prepare_projection_slot(AggState *aggstate,
TupleTableSlot *slot,
int currentSet);
static void finalize_aggregates(AggState *aggstate,
AggStatePerAgg peragg,
AggStatePerGroup pergroup);
static TupleTableSlot *project_aggregates(AggState *aggstate);
static Bitmapset *find_unaggregated_cols(AggState *aggstate);
static bool find_unaggregated_cols_walker(Node *node, Bitmapset **colnos);
static void build_hash_tables(AggState *aggstate);
static void build_hash_table(AggState *aggstate, int setno, long nbuckets);
static void hashagg_recompile_expressions(AggState *aggstate, bool minslot,
bool nullcheck);
static long hash_choose_num_buckets(double hashentrysize,
long estimated_nbuckets,
Size memory);
static int hash_choose_num_partitions(AggState *aggstate,
uint64 input_groups,
double hashentrysize,
int used_bits,
int *log2_npartittions);
static AggStatePerGroup lookup_hash_entry(AggState *aggstate, uint32 hash,
bool *in_hash_table);
static void lookup_hash_entries(AggState *aggstate);
static TupleTableSlot *agg_retrieve_direct(AggState *aggstate);
static void agg_fill_hash_table(AggState *aggstate);
static bool agg_refill_hash_table(AggState *aggstate);
static TupleTableSlot *agg_retrieve_hash_table(AggState *aggstate);
static TupleTableSlot *agg_retrieve_hash_table_in_memory(AggState *aggstate);
static void hash_agg_check_limits(AggState *aggstate);
static void hash_agg_enter_spill_mode(AggState *aggstate);
static void hash_agg_update_metrics(AggState *aggstate, bool from_tape,
int npartitions);
static void hashagg_finish_initial_spills(AggState *aggstate);
static void hashagg_reset_spill_state(AggState *aggstate);
static HashAggBatch *hashagg_batch_new(LogicalTapeSet *tapeset,
int input_tapenum, int setno,
int64 input_tuples, int used_bits);
static MinimalTuple hashagg_batch_read(HashAggBatch *batch, uint32 *hashp);
static void hashagg_spill_init(AggState *aggstate,
HashAggSpill *spill, HashTapeInfo *tapeinfo,
int used_bits, uint64 input_tuples,
double hashentrysize);
static Size hashagg_spill_tuple(HashAggSpill *spill, TupleTableSlot *slot,
uint32 hash);
static void hashagg_spill_finish(AggState *aggstate, HashAggSpill *spill,
int setno);
static void hashagg_tapeinfo_init(AggState *aggstate);
static void hashagg_tapeinfo_assign(HashTapeInfo *tapeinfo, int *dest,
int ndest);
static void hashagg_tapeinfo_release(HashTapeInfo *tapeinfo, int tapenum);
static Datum GetAggInitVal(Datum textInitVal, Oid transtype);
static void build_pertrans_for_aggref(AggStatePerTrans pertrans,
AggState *aggstate, EState *estate,
Aggref *aggref, Oid aggtransfn, Oid aggtranstype,
Oid aggserialfn, Oid aggdeserialfn,
Datum initValue, bool initValueIsNull,
Oid *inputTypes, int numArguments);
static int find_compatible_peragg(Aggref *newagg, AggState *aggstate,
int lastaggno, List **same_input_transnos);
static int find_compatible_pertrans(AggState *aggstate, Aggref *newagg,
bool shareable,
Oid aggtransfn, Oid aggtranstype,
Oid aggserialfn, Oid aggdeserialfn,
Datum initValue, bool initValueIsNull,
List *transnos);
static void ExecEagerFreeAgg(AggState *node);
/*
* Select the current grouping set; affects current_set and
* curaggcontext.
*/
static void
select_current_set(AggState *aggstate, int setno, bool is_hash)
{
/* when changing this, also adapt ExecInterpExpr() and friends */
if (is_hash)
aggstate->curaggcontext = aggstate->hashcontext;
else
aggstate->curaggcontext = aggstate->aggcontexts[setno];
aggstate->current_set = setno;
}
/*
* Switch to phase "newphase", which must either be 0 or 1 (to reset) or
* current_phase + 1. Juggle the tuplesorts accordingly.
*
* Phase 0 is for hashing, which we currently handle last in the AGG_MIXED
* case, so when entering phase 0, all we need to do is drop open sorts.
*/
static void
initialize_phase(AggState *aggstate, int newphase)
{
Assert(newphase <= 1 || newphase == aggstate->current_phase + 1);
/*
* Whatever the previous state, we're now done with whatever input
* tuplesort was in use.
*/
if (aggstate->sort_in)
{
tuplesort_end(aggstate->sort_in);
aggstate->sort_in = NULL;
}
if (newphase <= 1)
{
/*
* Discard any existing output tuplesort.
*/
if (aggstate->sort_out)
{
tuplesort_end(aggstate->sort_out);
aggstate->sort_out = NULL;
}
}
else
{
/*
* The old output tuplesort becomes the new input one, and this is the
* right time to actually sort it.
*/
aggstate->sort_in = aggstate->sort_out;
aggstate->sort_out = NULL;
Assert(aggstate->sort_in);
tuplesort_performsort(aggstate->sort_in);
}
/*
* If this isn't the last phase, we need to sort appropriately for the
* next phase in sequence.
*/
if (newphase > 0 && newphase < aggstate->numphases - 1)
{
Sort *sortnode = aggstate->phases[newphase + 1].sortnode;
PlanState *outerNode = outerPlanState(aggstate);
TupleDesc tupDesc = ExecGetResultType(outerNode);
aggstate->sort_out = tuplesort_begin_heap(tupDesc,
sortnode->numCols,
sortnode->sortColIdx,
sortnode->sortOperators,
sortnode->collations,
sortnode->nullsFirst,
PlanStateOperatorMemKB((PlanState *) aggstate),
NULL, false);
}
aggstate->current_phase = newphase;
aggstate->phase = &aggstate->phases[newphase];
}
/*
* Fetch a tuple from either the outer plan (for phase 1) or from the sorter
* populated by the previous phase. Copy it to the sorter for the next phase
* if any.
*
* Callers cannot rely on memory for tuple in returned slot remaining valid
* past any subsequently fetched tuple.
*/
static TupleTableSlot *
fetch_input_tuple(AggState *aggstate)
{
TupleTableSlot *slot;
if (aggstate->sort_in)
{
/* make sure we check for interrupts in either path through here */
CHECK_FOR_INTERRUPTS();
if (!tuplesort_gettupleslot(aggstate->sort_in, true, false,
aggstate->sort_slot, NULL))
return NULL;
slot = aggstate->sort_slot;
}
else
slot = ExecProcNode(outerPlanState(aggstate));
if (!TupIsNull(slot) && aggstate->sort_out)
tuplesort_puttupleslot(aggstate->sort_out, slot);
return slot;
}
/*
* (Re)Initialize an individual aggregate.
*
* This function handles only one grouping set, already set in
* aggstate->current_set.
*
* When called, CurrentMemoryContext should be the per-query context.
*/
static void
initialize_aggregate(AggState *aggstate, AggStatePerTrans pertrans,
AggStatePerGroup pergroupstate)
{
/*
* Start a fresh sort operation for each DISTINCT/ORDER BY aggregate.
*/
if (pertrans->numSortCols > 0)
{
/*
* In case of rescan, maybe there could be an uncompleted sort
* operation? Clean it up if so.
*/
if (pertrans->sortstates[aggstate->current_set])
tuplesort_end(pertrans->sortstates[aggstate->current_set]);
/*
* We use a plain Datum sorter when there's a single input column;
* otherwise sort the full tuple. (See comments for
* process_ordered_aggregate_single.)
*/
if (pertrans->numInputs == 1)
{
Form_pg_attribute attr = TupleDescAttr(pertrans->sortdesc, 0);
pertrans->sortstates[aggstate->current_set] =
tuplesort_begin_datum(attr->atttypid,
pertrans->sortOperators[0],
pertrans->sortCollations[0],
pertrans->sortNullsFirst[0],
PlanStateOperatorMemKB((PlanState *) aggstate), NULL, false);
}
else
pertrans->sortstates[aggstate->current_set] =
tuplesort_begin_heap(pertrans->sortdesc,
pertrans->numSortCols,
pertrans->sortColIdx,
pertrans->sortOperators,
pertrans->sortCollations,
pertrans->sortNullsFirst,
PlanStateOperatorMemKB((PlanState *) aggstate), NULL, false);
}
/*
* (Re)set transValue to the initial value.
*
* Note that when the initial value is pass-by-ref, we must copy
* it (into the aggcontext) since we will pfree the transValue
* later.
*/
if (pertrans->initValueIsNull)
pergroupstate->transValue = pertrans->initValue;
else
{
MemoryContext oldContext;
oldContext = MemoryContextSwitchTo(
aggstate->curaggcontext->ecxt_per_tuple_memory);
pergroupstate->transValue = datumCopy(pertrans->initValue,
pertrans->transtypeByVal,
pertrans->transtypeLen);
MemoryContextSwitchTo(oldContext);
}
pergroupstate->transValueIsNull = pertrans->initValueIsNull;
/*
* If the initial value for the transition state doesn't exist in the
* pg_aggregate table then we will let the first non-NULL value returned
* from the outer procNode become the initial value. (This is useful for
* aggregates like max() and min().) The noTransValue flag signals that we
* still need to do this.
*/
pergroupstate->noTransValue = pertrans->initValueIsNull;
}
/*
* Initialize all aggregate transition states for a new group of input values.
*
* If there are multiple grouping sets, we initialize only the first numReset
* of them (the grouping sets are ordered so that the most specific one, which
* is reset most often, is first). As a convenience, if numReset is 0, we
* reinitialize all sets.
*
* NB: This cannot be used for hash aggregates, as for those the grouping set
* number has to be specified from further up.
*
* When called, CurrentMemoryContext should be the per-query context.
*/
static void
initialize_aggregates(AggState *aggstate,
AggStatePerGroup *pergroups,
int numReset)
{
int transno;
int numGroupingSets = Max(aggstate->phase->numsets, 1);
int setno = 0;
int numTrans = aggstate->numtrans;
AggStatePerTrans transstates = aggstate->pertrans;
if (numReset == 0)
numReset = numGroupingSets;
for (setno = 0; setno < numReset; setno++)
{
AggStatePerGroup pergroup = pergroups[setno];
select_current_set(aggstate, setno, false);
for (transno = 0; transno < numTrans; transno++)
{
AggStatePerTrans pertrans = &transstates[transno];
AggStatePerGroup pergroupstate = &pergroup[transno];
initialize_aggregate(aggstate, pertrans, pergroupstate);
}
}
}
/*
* Given new input value(s), advance the transition function of one aggregate
* state within one grouping set only (already set in aggstate->current_set)
*
* The new values (and null flags) have been preloaded into argument positions
* 1 and up in pertrans->transfn_fcinfo, so that we needn't copy them again to
* pass to the transition function. We also expect that the static fields of
* the fcinfo are already initialized; that was done by ExecInitAgg().
*
* It doesn't matter which memory context this is called in.
*/
static void
advance_transition_function(AggState *aggstate,
AggStatePerTrans pertrans,
AggStatePerGroup pergroupstate)
{
FunctionCallInfo fcinfo = pertrans->transfn_fcinfo;
MemoryContext oldContext;
Datum newVal;
if (pertrans->transfn.fn_strict)
{
/*
* For a strict transfn, nothing happens when there's a NULL input; we
* just keep the prior transValue.
*/
int numTransInputs = pertrans->numTransInputs;
int i;
for (i = 1; i <= numTransInputs; i++)
{
if (fcinfo->args[i].isnull)
return;
}
if (pergroupstate->noTransValue)
{
/*
* transValue has not been initialized. This is the first non-NULL
* input value. We use it as the initial value for transValue. (We
* already checked that the agg's input type is binary-compatible
* with its transtype, so straight copy here is OK.)
*
* We must copy the datum into aggcontext if it is pass-by-ref. We
* do not need to pfree the old transValue, since it's NULL.
*/
oldContext = MemoryContextSwitchTo(
aggstate->curaggcontext->ecxt_per_tuple_memory);
pergroupstate->transValue = datumCopy(fcinfo->args[1].value,
pertrans->transtypeByVal,
pertrans->transtypeLen);
pergroupstate->transValueIsNull = false;
pergroupstate->noTransValue = false;
MemoryContextSwitchTo(oldContext);
return;
}
if (pergroupstate->transValueIsNull)
{
/*
* Don't call a strict function with NULL inputs. Note it is
* possible to get here despite the above tests, if the transfn is
* strict *and* returned a NULL on a prior cycle. If that happens
* we will propagate the NULL all the way to the end.
*/
return;
}
}
/* We run the transition functions in per-input-tuple memory context */
oldContext = MemoryContextSwitchTo(aggstate->tmpcontext->ecxt_per_tuple_memory);
/* set up aggstate->curpertrans for AggGetAggref() */
aggstate->curpertrans = pertrans;
/*
* OK to call the transition function
*/
fcinfo->args[0].value = pergroupstate->transValue;
fcinfo->args[0].isnull = pergroupstate->transValueIsNull;
fcinfo->isnull = false; /* just in case transfn doesn't set it */
newVal = FunctionCallInvoke(fcinfo);
aggstate->curpertrans = NULL;
/*
* If pass-by-ref datatype, must copy the new value into aggcontext and
* free the prior transValue. But if transfn returned a pointer to its
* first input, we don't need to do anything. Also, if transfn returned a
* pointer to a R/W expanded object that is already a child of the
* aggcontext, assume we can adopt that value without copying it.
*
* It's safe to compare newVal with pergroup->transValue without
* regard for either being NULL, because ExecAggTransReparent()
* takes care to set transValue to 0 when NULL. Otherwise we could
* end up accidentally not reparenting, when the transValue has
* the same numerical value as newValue, despite being NULL. This
* is a somewhat hot path, making it undesirable to instead solve
* this with another branch for the common case of the transition
* function returning its (modified) input argument.
*/
if (!pertrans->transtypeByVal &&
DatumGetPointer(newVal) != DatumGetPointer(pergroupstate->transValue))
newVal = ExecAggTransReparent(aggstate, pertrans,
newVal, fcinfo->isnull,
pergroupstate->transValue,
pergroupstate->transValueIsNull);
pergroupstate->transValue = newVal;
pergroupstate->transValueIsNull = fcinfo->isnull;
MemoryContextSwitchTo(oldContext);
}
/*
* Advance each aggregate transition state for one input tuple. The input
* tuple has been stored in tmpcontext->ecxt_outertuple, so that it is
* accessible to ExecEvalExpr.
*
* We have two sets of transition states to handle: one for sorted aggregation
* and one for hashed; we do them both here, to avoid multiple evaluation of
* the inputs.
*
* When called, CurrentMemoryContext should be the per-query context.
*/
static void
advance_aggregates(AggState *aggstate)
{
bool dummynull;
ExecEvalExprSwitchContext(aggstate->phase->evaltrans,
aggstate->tmpcontext,
&dummynull);
}
/*
* Run the transition function for a DISTINCT or ORDER BY aggregate
* with only one input. This is called after we have completed
* entering all the input values into the sort object. We complete the
* sort, read out the values in sorted order, and run the transition
* function on each value (applying DISTINCT if appropriate).
*
* Note that the strictness of the transition function was checked when
* entering the values into the sort, so we don't check it again here;
* we just apply standard SQL DISTINCT logic.
*
* The one-input case is handled separately from the multi-input case
* for performance reasons: for single by-value inputs, such as the
* common case of count(distinct id), the tuplesort_getdatum code path
* is around 300% faster. (The speedup for by-reference types is less
* but still noticeable.)
*
* This function handles only one grouping set (already set in
* aggstate->current_set).
*
* When called, CurrentMemoryContext should be the per-query context.
*/
static void
process_ordered_aggregate_single(AggState *aggstate,
AggStatePerTrans pertrans,
AggStatePerGroup pergroupstate)
{
Datum oldVal = (Datum) 0;
bool oldIsNull = true;
bool haveOldVal = false;
MemoryContext workcontext = aggstate->tmpcontext->ecxt_per_tuple_memory;
MemoryContext oldContext;
bool isDistinct = (pertrans->numDistinctCols > 0);
Datum newAbbrevVal = (Datum) 0;
Datum oldAbbrevVal = (Datum) 0;
FunctionCallInfo fcinfo = pertrans->transfn_fcinfo;
Datum *newVal;
bool *isNull;
Assert(pertrans->numDistinctCols < 2);
tuplesort_performsort(pertrans->sortstates[aggstate->current_set]);
/* Load the column into argument 1 (arg 0 will be transition value) */
newVal = &fcinfo->args[1].value;
isNull = &fcinfo->args[1].isnull;
/*
* Note: if input type is pass-by-ref, the datums returned by the sort are
* freshly palloc'd in the per-query context, so we must be careful to
* pfree them when they are no longer needed.
*/
while (tuplesort_getdatum(pertrans->sortstates[aggstate->current_set],
true, newVal, isNull, &newAbbrevVal))
{
/*
* Clear and select the working context for evaluation of the equality
* function and transition function.
*/
MemoryContextReset(workcontext);
oldContext = MemoryContextSwitchTo(workcontext);
/*
* If DISTINCT mode, and not distinct from prior, skip it.
*/
if (isDistinct &&
haveOldVal &&
((oldIsNull && *isNull) ||
(!oldIsNull && !*isNull &&
oldAbbrevVal == newAbbrevVal &&
DatumGetBool(FunctionCall2Coll(&pertrans->equalfnOne,
pertrans->aggCollation,
oldVal, *newVal)))))
{
/* equal to prior, so forget this one */
if (!pertrans->inputtypeByVal && !*isNull)
pfree(DatumGetPointer(*newVal));
}
else
{
advance_transition_function(aggstate, pertrans, pergroupstate);
/* forget the old value, if any */
if (!oldIsNull && !pertrans->inputtypeByVal)
pfree(DatumGetPointer(oldVal));
/* and remember the new one for subsequent equality checks */
oldVal = *newVal;
oldAbbrevVal = newAbbrevVal;
oldIsNull = *isNull;
haveOldVal = true;
}
MemoryContextSwitchTo(oldContext);
}
if (!oldIsNull && !pertrans->inputtypeByVal)
pfree(DatumGetPointer(oldVal));
tuplesort_end(pertrans->sortstates[aggstate->current_set]);
pertrans->sortstates[aggstate->current_set] = NULL;
}
/*
* Run the transition function for a DISTINCT or ORDER BY aggregate
* with more than one input. This is called after we have completed
* entering all the input values into the sort object. We complete the
* sort, read out the values in sorted order, and run the transition
* function on each value (applying DISTINCT if appropriate).
*
* This function handles only one grouping set (already set in
* aggstate->current_set).
*
* When called, CurrentMemoryContext should be the per-query context.
*/
static void
process_ordered_aggregate_multi(AggState *aggstate,
AggStatePerTrans pertrans,
AggStatePerGroup pergroupstate)
{
ExprContext *tmpcontext = aggstate->tmpcontext;
FunctionCallInfo fcinfo = pertrans->transfn_fcinfo;
TupleTableSlot *slot1 = pertrans->sortslot;
TupleTableSlot *slot2 = pertrans->uniqslot;
int numTransInputs = pertrans->numTransInputs;
int numDistinctCols = pertrans->numDistinctCols;
Datum newAbbrevVal = (Datum) 0;
Datum oldAbbrevVal = (Datum) 0;
bool haveOldValue = false;
TupleTableSlot *save = aggstate->tmpcontext->ecxt_outertuple;
int i;
tuplesort_performsort(pertrans->sortstates[aggstate->current_set]);
ExecClearTuple(slot1);
if (slot2)
ExecClearTuple(slot2);
while (tuplesort_gettupleslot(pertrans->sortstates[aggstate->current_set],
true, true, slot1, &newAbbrevVal))
{
CHECK_FOR_INTERRUPTS();
tmpcontext->ecxt_outertuple = slot1;
tmpcontext->ecxt_innertuple = slot2;
if (numDistinctCols == 0 ||
!haveOldValue ||
newAbbrevVal != oldAbbrevVal ||
!ExecQual(pertrans->equalfnMulti, tmpcontext))
{
/*
* Extract the first numTransInputs columns as datums to pass to
* the transfn.
*/
slot_getsomeattrs(slot1, numTransInputs);
/* Load values into fcinfo */
/* Start from 1, since the 0th arg will be the transition value */
for (i = 0; i < numTransInputs; i++)
{
fcinfo->args[i + 1].value = slot1->tts_values[i];
fcinfo->args[i + 1].isnull = slot1->tts_isnull[i];
}
advance_transition_function(aggstate, pertrans, pergroupstate);
if (numDistinctCols > 0)
{
/* swap the slot pointers to retain the current tuple */
TupleTableSlot *tmpslot = slot2;
slot2 = slot1;
slot1 = tmpslot;
/* avoid ExecQual() calls by reusing abbreviated keys */
oldAbbrevVal = newAbbrevVal;
haveOldValue = true;
}
}
/* Reset context each time */
ResetExprContext(tmpcontext);
ExecClearTuple(slot1);
}
if (slot2)
ExecClearTuple(slot2);
tuplesort_end(pertrans->sortstates[aggstate->current_set]);
pertrans->sortstates[aggstate->current_set] = NULL;
/* restore previous slot, potentially in use for grouping sets */
tmpcontext->ecxt_outertuple = save;
}
/*
* Compute the final value of one aggregate.
*
* This function handles only one grouping set (already set in
* aggstate->current_set).
*
* The finalfunction will be run, and the result delivered, in the
* output-tuple context; caller's CurrentMemoryContext does not matter.
*
* The finalfn uses the state as set in the transno. This also might be
* being used by another aggregate function, so it's important that we do
* nothing destructive here.
*/
static void
finalize_aggregate(AggState *aggstate,
AggStatePerAgg peragg,
AggStatePerGroup pergroupstate,
Datum *resultVal, bool *resultIsNull)
{
LOCAL_FCINFO(fcinfo, FUNC_MAX_ARGS);
bool anynull = false;
MemoryContext oldContext;
int i;
ListCell *lc;
AggStatePerTrans pertrans = &aggstate->pertrans[peragg->transno];
oldContext = MemoryContextSwitchTo(aggstate->ss.ps.ps_ExprContext->ecxt_per_tuple_memory);
/*
* Evaluate any direct arguments. We do this even if there's no finalfn
* (which is unlikely anyway), so that side-effects happen as expected.
* The direct arguments go into arg positions 1 and up, leaving position 0
* for the transition state value.
*/
i = 1;
foreach(lc, peragg->aggdirectargs)
{
ExprState *expr = (ExprState *) lfirst(lc);
fcinfo->args[i].value = ExecEvalExpr(expr,
aggstate->ss.ps.ps_ExprContext,
&fcinfo->args[i].isnull);
anynull |= fcinfo->args[i].isnull;
i++;
}
/*
* Apply the agg's finalfn if one is provided, else return transValue.
*/
if (OidIsValid(peragg->finalfn_oid))
{
int numFinalArgs = peragg->numFinalArgs;
/* set up aggstate->curperagg for AggGetAggref() */
aggstate->curperagg = peragg;
InitFunctionCallInfoData(*fcinfo, &peragg->finalfn,
numFinalArgs,
pertrans->aggCollation,
(void *) aggstate, NULL);
/* Fill in the transition state value */
fcinfo->args[0].value =
MakeExpandedObjectReadOnly(pergroupstate->transValue,
pergroupstate->transValueIsNull,
pertrans->transtypeLen);
fcinfo->args[0].isnull = pergroupstate->transValueIsNull;
anynull |= pergroupstate->transValueIsNull;
/* Fill any remaining argument positions with nulls */
for (; i < numFinalArgs; i++)
{
fcinfo->args[i].value = (Datum) 0;
fcinfo->args[i].isnull = true;
anynull = true;
}
if (fcinfo->flinfo->fn_strict && anynull)
{
/* don't call a strict function with NULL inputs */
*resultVal = (Datum) 0;
*resultIsNull = true;
}
else
{
*resultVal = FunctionCallInvoke(fcinfo);
*resultIsNull = fcinfo->isnull;
}
aggstate->curperagg = NULL;
}
/*
* serialfn_oid will be set if we must serialize the transvalue before
* returning it
*/
else if (OidIsValid(pertrans->serialfn_oid))
{
/* Don't call a strict serialization function with NULL input. */
if (pertrans->serialfn.fn_strict && pergroupstate->transValueIsNull)
{
*resultVal = (Datum) 0;
*resultIsNull = true;
}
else
{
InitFunctionCallInfoData(*fcinfo,
&pertrans->serialfn,
1,
InvalidOid,
(void *) aggstate, NULL);
fcinfo->args[0].value = pergroupstate->transValue;
fcinfo->args[0].isnull = pergroupstate->transValueIsNull;
*resultVal = FunctionCallInvoke(fcinfo);
*resultIsNull = fcinfo->args[0].isnull;
}
}
else
{
/* Don't need MakeExpandedObjectReadOnly; datumCopy will copy it */
*resultVal = pergroupstate->transValue;
*resultIsNull = pergroupstate->transValueIsNull;
}
/*
* If result is pass-by-ref, make sure it is in the right context.
*/
if (!peragg->resulttypeByVal && !*resultIsNull &&
!MemoryContextContainsGenericAllocation(CurrentMemoryContext,
DatumGetPointer(*resultVal)))
*resultVal = datumCopy(*resultVal,
peragg->resulttypeByVal,
peragg->resulttypeLen);
MemoryContextSwitchTo(oldContext);
}
/*
* Compute the output value of one partial aggregate.
*
* The serialization function will be run, and the result delivered, in the
* output-tuple context; caller's CurrentMemoryContext does not matter.
*/
static void
finalize_partialaggregate(AggState *aggstate,
AggStatePerAgg peragg,
AggStatePerGroup pergroupstate,
Datum *resultVal, bool *resultIsNull)
{
AggStatePerTrans pertrans = &aggstate->pertrans[peragg->transno];
MemoryContext oldContext;
oldContext = MemoryContextSwitchTo(aggstate->ss.ps.ps_ExprContext->ecxt_per_tuple_memory);
/*
* serialfn_oid will be set if we must serialize the transvalue before
* returning it
*/
if (OidIsValid(pertrans->serialfn_oid))
{
/* Don't call a strict serialization function with NULL input. */
if (pertrans->serialfn.fn_strict && pergroupstate->transValueIsNull)
{
*resultVal = (Datum) 0;
*resultIsNull = true;
}
else
{
FunctionCallInfo fcinfo = pertrans->serialfn_fcinfo;
fcinfo->args[0].value =
MakeExpandedObjectReadOnly(pergroupstate->transValue,
pergroupstate->transValueIsNull,
pertrans->transtypeLen);
fcinfo->args[0].isnull = pergroupstate->transValueIsNull;
*resultVal = FunctionCallInvoke(fcinfo);
*resultIsNull = fcinfo->isnull;
}
}
else
{
/* Don't need MakeExpandedObjectReadOnly; datumCopy will copy it */
*resultVal = pergroupstate->transValue;
*resultIsNull = pergroupstate->transValueIsNull;
}
/* If result is pass-by-ref, make sure it is in the right context. */
if (!peragg->resulttypeByVal && !*resultIsNull &&
!MemoryContextContainsGenericAllocation(CurrentMemoryContext,
DatumGetPointer(*resultVal)))
*resultVal = datumCopy(*resultVal,
peragg->resulttypeByVal,
peragg->resulttypeLen);
MemoryContextSwitchTo(oldContext);
}
/*
* Extract the attributes that make up the grouping key into the
* hashslot. This is necessary to compute the hash or perform a lookup.
*/
static void
prepare_hash_slot(AggState *aggstate)
{
TupleTableSlot *inputslot = aggstate->tmpcontext->ecxt_outertuple;
AggStatePerHash perhash = &aggstate->perhash[aggstate->current_set];
TupleTableSlot *hashslot = perhash->hashslot;
int i;
/* transfer just the needed columns into hashslot */
slot_getsomeattrs(inputslot, perhash->largestGrpColIdx);
ExecClearTuple(hashslot);
for (i = 0; i < perhash->numhashGrpCols; i++)
{
int varNumber = perhash->hashGrpColIdxInput[i] - 1;
hashslot->tts_values[i] = inputslot->tts_values[varNumber];
hashslot->tts_isnull[i] = inputslot->tts_isnull[varNumber];
}
ExecStoreVirtualTuple(hashslot);
}
/*
* Prepare to finalize and project based on the specified representative tuple
* slot and grouping set.
*
* In the specified tuple slot, force to null all attributes that should be
* read as null in the context of the current grouping set. Also stash the
* current group bitmap where GroupingExpr can get at it.
*
* This relies on three conditions:
*
* 1) Nothing is ever going to try and extract the whole tuple from this slot,
* only reference it in evaluations, which will only access individual
* attributes.
*
* 2) No system columns are going to need to be nulled. (If a system column is
* referenced in a group clause, it is actually projected in the outer plan
* tlist.)
*
* 3) Within a given phase, we never need to recover the value of an attribute
* once it has been set to null.
*
* Poking into the slot this way is a bit ugly, but the consensus is that the
* alternative was worse.
*/
static void
prepare_projection_slot(AggState *aggstate, TupleTableSlot *slot, int currentSet)
{
if (aggstate->phase->grouped_cols)
{
Bitmapset *grouped_cols = aggstate->phase->grouped_cols[currentSet];
aggstate->grouped_cols = grouped_cols;
aggstate->group_id = aggstate->phase->group_id[currentSet];
aggstate->gset_id = aggstate->phase->gset_id[currentSet];
if (TTS_EMPTY(slot))
{
/*
* Force all values to be NULL if working on an empty input tuple
* (i.e. an empty grouping set for which no input rows were
* supplied).
*/
ExecStoreAllNullTuple(slot);
}
else if (aggstate->all_grouped_cols)
{
ListCell *lc;
/* all_grouped_cols is arranged in desc order */
slot_getsomeattrs(slot, linitial_int(aggstate->all_grouped_cols));
foreach(lc, aggstate->all_grouped_cols)
{
int attnum = lfirst_int(lc);
if (!bms_is_member(attnum, grouped_cols))
slot->tts_isnull[attnum - 1] = true;
}
}
}
}
/*
* Compute the final value of all aggregates for one group.
*
* This function handles only one grouping set at a time, which the caller must
* have selected. It's also the caller's responsibility to adjust the supplied
* pergroup parameter to point to the current set's transvalues.
*
* Results are stored in the output econtext aggvalues/aggnulls.
*/
static void
finalize_aggregates(AggState *aggstate,
AggStatePerAgg peraggs,
AggStatePerGroup pergroup)
{
ExprContext *econtext = aggstate->ss.ps.ps_ExprContext;
Datum *aggvalues = econtext->ecxt_aggvalues;
bool *aggnulls = econtext->ecxt_aggnulls;
int aggno;
int transno;
/*
* If there were any DISTINCT and/or ORDER BY aggregates, sort their
* inputs and run the transition functions.
*/
for (transno = 0; transno < aggstate->numtrans; transno++)
{
AggStatePerTrans pertrans = &aggstate->pertrans[transno];
AggStatePerGroup pergroupstate;
pergroupstate = &pergroup[transno];
if (pertrans->numSortCols > 0)
{
Assert(aggstate->aggstrategy != AGG_HASHED &&
aggstate->aggstrategy != AGG_MIXED);
if (pertrans->numInputs == 1)
process_ordered_aggregate_single(aggstate,
pertrans,
pergroupstate);
else
process_ordered_aggregate_multi(aggstate,
pertrans,
pergroupstate);
}
}
/*
* Run the final functions.
*/
for (aggno = 0; aggno < aggstate->numaggs; aggno++)
{
AggStatePerAgg peragg = &peraggs[aggno];
int transno = peragg->transno;
AggStatePerGroup pergroupstate;
pergroupstate = &pergroup[transno];
if (DO_AGGSPLIT_SKIPFINAL(aggstate->aggsplit))
finalize_partialaggregate(aggstate, peragg, pergroupstate,
&aggvalues[aggno], &aggnulls[aggno]);
else
finalize_aggregate(aggstate, peragg, pergroupstate,
&aggvalues[aggno], &aggnulls[aggno]);
}
}
/*
* Project the result of a group (whose aggs have already been calculated by
* finalize_aggregates). Returns the result slot, or NULL if no row is
* projected (suppressed by qual).
*/
static TupleTableSlot *
project_aggregates(AggState *aggstate)
{
ExprContext *econtext = aggstate->ss.ps.ps_ExprContext;
/*
* Check the qual (HAVING clause); if the group does not match, ignore it.
*/
if (ExecQual(aggstate->ss.ps.qual, econtext))
{
/*
* Form and return projection tuple using the aggregate results and
* the representative input tuple.
*/
return ExecProject(aggstate->ss.ps.ps_ProjInfo);
}
else
InstrCountFiltered1(aggstate, 1);
return NULL;
}
/*
* find_unaggregated_cols
* Construct a bitmapset of the column numbers of un-aggregated Vars
* appearing in our targetlist and qual (HAVING clause)
*/
static Bitmapset *
find_unaggregated_cols(AggState *aggstate)
{
Agg *node = (Agg *) aggstate->ss.ps.plan;
Bitmapset *colnos;
colnos = NULL;
(void) find_unaggregated_cols_walker((Node *) node->plan.targetlist,
&colnos);
(void) find_unaggregated_cols_walker((Node *) node->plan.qual,
&colnos);
return colnos;
}
static bool
find_unaggregated_cols_walker(Node *node, Bitmapset **colnos)
{
if (node == NULL)
return false;
if (IsA(node, Var))
{
Var *var = (Var *) node;
/* setrefs.c should have set the varno to OUTER_VAR */
Assert(var->varno == OUTER_VAR);
Assert(var->varlevelsup == 0);
*colnos = bms_add_member(*colnos, var->varattno);
return false;
}
if (IsA(node, Aggref) || IsA(node, GroupingFunc))
{
/* do not descend into aggregate exprs */
return false;
}
return expression_tree_walker(node, find_unaggregated_cols_walker,
(void *) colnos);
}
/*
* (Re-)initialize the hash table(s) to empty.
*
* To implement hashed aggregation, we need a hashtable that stores a
* representative tuple and an array of AggStatePerGroup structs for each
* distinct set of GROUP BY column values. We compute the hash key from the
* GROUP BY columns. The per-group data is allocated in lookup_hash_entry(),
* for each entry.
*
* We have a separate hashtable and associated perhash data structure for each
* grouping set for which we're doing hashing.
*
* The contents of the hash tables always live in the hashcontext's per-tuple
* memory context (there is only one of these for all tables together, since
* they are all reset at the same time).
*/
static void
build_hash_tables(AggState *aggstate)
{
int setno;
for (setno = 0; setno < aggstate->num_hashes; ++setno)
{
AggStatePerHash perhash = &aggstate->perhash[setno];
long nbuckets;
Size memory;
if (perhash->hashtable != NULL)
{
ResetTupleHashTable(perhash->hashtable);
continue;
}
Assert(perhash->aggnode->numGroups > 0);
memory = aggstate->hash_mem_limit / aggstate->num_hashes;
/* choose reasonable number of buckets per hashtable */
nbuckets = hash_choose_num_buckets(
aggstate->hashentrysize, perhash->aggnode->numGroups, memory);
build_hash_table(aggstate, setno, nbuckets);
}
aggstate->hash_ngroups_current = 0;
}
/*
* Build a single hashtable for this grouping set.
*/
static void
build_hash_table(AggState *aggstate, int setno, long nbuckets)
{
AggStatePerHash perhash = &aggstate->perhash[setno];
MemoryContext metacxt = aggstate->hash_metacxt;
MemoryContext hashcxt = aggstate->hashcontext->ecxt_per_tuple_memory;
MemoryContext tmpcxt = aggstate->tmpcontext->ecxt_per_tuple_memory;
Size additionalsize;
Assert(aggstate->aggstrategy == AGG_HASHED ||
aggstate->aggstrategy == AGG_MIXED);
/*
* Used to make sure initial hash table allocation does not exceed
* work_mem. Note that the estimate does not include space for
* pass-by-reference transition data values, nor for the representative
* tuple of each group.
*/
additionalsize = aggstate->numtrans * sizeof(AggStatePerGroupData);
perhash->hashtable = BuildTupleHashTableExt(
&aggstate->ss.ps,
perhash->hashslot->tts_tupleDescriptor,
perhash->numCols,
perhash->hashGrpColIdxHash,
perhash->eqfuncoids,
perhash->hashfunctions,
perhash->aggnode->grpCollations,
nbuckets,
additionalsize,
metacxt,
hashcxt,
tmpcxt,
DO_AGGSPLIT_SKIPFINAL(aggstate->aggsplit));
}
/*
* Compute columns that actually need to be stored in hashtable entries. The
* incoming tuples from the child plan node will contain grouping columns,
* other columns referenced in our targetlist and qual, columns used to
* compute the aggregate functions, and perhaps just junk columns we don't use
* at all. Only columns of the first two types need to be stored in the
* hashtable, and getting rid of the others can make the table entries
* significantly smaller. The hashtable only contains the relevant columns,
* and is packed/unpacked in lookup_hash_entry() / agg_retrieve_hash_table()
* into the format of the normal input descriptor.
*
* Additional columns, in addition to the columns grouped by, come from two
* sources: Firstly functionally dependent columns that we don't need to group
* by themselves, and secondly ctids for row-marks.
*
* To eliminate duplicates, we build a bitmapset of the needed columns, and
* then build an array of the columns included in the hashtable. We might
* still have duplicates if the passed-in grpColIdx has them, which can happen
* in edge cases from semijoins/distinct; these can't always be removed,
* because it's not certain that the duplicate cols will be using the same
* hash function.
*
* Note that the array is preserved over ExecReScanAgg, so we allocate it in
* the per-query context (unlike the hash table itself).
*/
static void
find_hash_columns(AggState *aggstate)
{
Bitmapset *base_colnos;
List *outerTlist = outerPlanState(aggstate)->plan->targetlist;
int numHashes = aggstate->num_hashes;
EState *estate = aggstate->ss.ps.state;
int j;
/* Find Vars that will be needed in tlist and qual */
base_colnos = find_unaggregated_cols(aggstate);
for (j = 0; j < numHashes; ++j)
{
AggStatePerHash perhash = &aggstate->perhash[j];
Bitmapset *colnos = bms_copy(base_colnos);
AttrNumber *grpColIdx = perhash->aggnode->grpColIdx;
List *hashTlist = NIL;
TupleDesc hashDesc;
int maxCols;
int i;
perhash->largestGrpColIdx = 0;
/*
* If we're doing grouping sets, then some Vars might be referenced in
* tlist/qual for the benefit of other grouping sets, but not needed
* when hashing; i.e. prepare_projection_slot will null them out, so
* there'd be no point storing them. Use prepare_projection_slot's
* logic to determine which.
*/
if (aggstate->phases[0].grouped_cols)
{
Bitmapset *grouped_cols = aggstate->phases[0].grouped_cols[j];
ListCell *lc;
foreach(lc, aggstate->all_grouped_cols)
{
int attnum = lfirst_int(lc);
if (!bms_is_member(attnum, grouped_cols))
colnos = bms_del_member(colnos, attnum);
}
}
/*
* Compute maximum number of input columns accounting for possible
* duplications in the grpColIdx array, which can happen in some edge
* cases where HashAggregate was generated as part of a semijoin or a
* DISTINCT.
*/
maxCols = bms_num_members(colnos) + perhash->numCols;
perhash->hashGrpColIdxInput =
palloc(maxCols * sizeof(AttrNumber));
perhash->hashGrpColIdxHash =
palloc(perhash->numCols * sizeof(AttrNumber));
/* Add all the grouping columns to colnos */
for (i = 0; i < perhash->numCols; i++)
colnos = bms_add_member(colnos, grpColIdx[i]);
/*
* First build mapping for columns directly hashed. These are the
* first, because they'll be accessed when computing hash values and
* comparing tuples for exact matches. We also build simple mapping
* for execGrouping, so it knows where to find the to-be-hashed /
* compared columns in the input.
*/
for (i = 0; i < perhash->numCols; i++)
{
perhash->hashGrpColIdxInput[i] = grpColIdx[i];
perhash->hashGrpColIdxHash[i] = i + 1;
perhash->numhashGrpCols++;
/* delete already mapped columns */
bms_del_member(colnos, grpColIdx[i]);
}
/* and add the remaining columns */
while ((i = bms_first_member(colnos)) >= 0)
{
perhash->hashGrpColIdxInput[perhash->numhashGrpCols] = i;
perhash->numhashGrpCols++;
}
/* and build a tuple descriptor for the hashtable */
for (i = 0; i < perhash->numhashGrpCols; i++)
{
int varNumber = perhash->hashGrpColIdxInput[i] - 1;
hashTlist = lappend(hashTlist, list_nth(outerTlist, varNumber));
perhash->largestGrpColIdx =
Max(varNumber + 1, perhash->largestGrpColIdx);
}
hashDesc = ExecTypeFromTL(hashTlist);
execTuplesHashPrepare(perhash->numCols,
perhash->aggnode->grpOperators,
&perhash->eqfuncoids,
&perhash->hashfunctions);
perhash->hashslot =
ExecAllocTableSlot(&estate->es_tupleTable, hashDesc,
&TTSOpsMinimalTuple);
list_free(hashTlist);
bms_free(colnos);
}
bms_free(base_colnos);
}
/*
* Estimate per-hash-table-entry overhead.
*/
Size
hash_agg_entry_size(int numTrans, Size tupleWidth, Size transitionSpace)
{
Size tupleChunkSize;
Size pergroupChunkSize;
Size transitionChunkSize;
Size tupleSize = (MAXALIGN(SizeofMinimalTupleHeader) +
tupleWidth);
Size pergroupSize = numTrans * sizeof(AggStatePerGroupData);
tupleChunkSize = CHUNKHDRSZ + tupleSize;
if (pergroupSize > 0)
pergroupChunkSize = CHUNKHDRSZ + pergroupSize;
else
pergroupChunkSize = 0;
if (transitionSpace > 0)
transitionChunkSize = CHUNKHDRSZ + transitionSpace;
else
transitionChunkSize = 0;
return
sizeof(TupleHashEntryData) +
tupleChunkSize +
pergroupChunkSize +
transitionChunkSize;
}
/*
* hashagg_recompile_expressions()
*
* Identifies the right phase, compiles the right expression given the
* arguments, and then sets phase->evalfunc to that expression.
*
* Different versions of the compiled expression are needed depending on
* whether hash aggregation has spilled or not, and whether it's reading from
* the outer plan or a tape. Before spilling to disk, the expression reads
* from the outer plan and does not need to perform a NULL check. After
* HashAgg begins to spill, new groups will not be created in the hash table,
* and the AggStatePerGroup array may be NULL; therefore we need to add a null
* pointer check to the expression. Then, when reading spilled data from a
* tape, we change the outer slot type to be a fixed minimal tuple slot.
*
* It would be wasteful to recompile every time, so cache the compiled
* expressions in the AggStatePerPhase, and reuse when appropriate.
*/
static void
hashagg_recompile_expressions(AggState *aggstate, bool minslot, bool nullcheck)
{
AggStatePerPhase phase;
int i = minslot ? 1 : 0;
int j = nullcheck ? 1 : 0;
Assert(aggstate->aggstrategy == AGG_HASHED ||
aggstate->aggstrategy == AGG_MIXED);
if (aggstate->aggstrategy == AGG_HASHED)
phase = &aggstate->phases[0];
else /* AGG_MIXED */
phase = &aggstate->phases[1];
if (phase->evaltrans_cache[i][j] == NULL)
{
const TupleTableSlotOps *outerops = aggstate->ss.ps.outerops;
bool outerfixed = aggstate->ss.ps.outeropsfixed;
bool dohash = true;
bool dosort;
dosort = aggstate->aggstrategy == AGG_MIXED ? true : false;
/* temporarily change the outerops while compiling the expression */
if (minslot)
{
aggstate->ss.ps.outerops = &TTSOpsMinimalTuple;
aggstate->ss.ps.outeropsfixed = true;
}
phase->evaltrans_cache[i][j] = ExecBuildAggTrans(aggstate, phase,
dosort, dohash,
nullcheck);
/* change back */
aggstate->ss.ps.outerops = outerops;
aggstate->ss.ps.outeropsfixed = outerfixed;
}
phase->evaltrans = phase->evaltrans_cache[i][j];
}
/*
* Set limits that trigger spilling to avoid exceeding work_mem. Consider the
* number of partitions we expect to create (if we do spill).
*
* There are two limits: a memory limit, and also an ngroups limit. The
* ngroups limit becomes important when we expect transition values to grow
* substantially larger than the initial value.
*/
void
hash_agg_set_limits(AggState *aggstate, double hashentrysize, uint64 input_groups, int used_bits,
Size *mem_limit, uint64 *ngroups_limit,
int *num_partitions)
{
int npartitions;
Size partition_mem;
uint64 strict_memlimit = work_mem;
if (aggstate)
{
uint64 operator_mem = PlanStateOperatorMemKB((PlanState *) aggstate);
if (operator_mem < strict_memlimit)
strict_memlimit = operator_mem;
}
/* if not expected to spill, use all of work_mem */
if (input_groups * hashentrysize < strict_memlimit * 1024L)
{
if (num_partitions != NULL)
*num_partitions = 0;
*mem_limit = strict_memlimit * 1024L;
*ngroups_limit = *mem_limit / hashentrysize;
return;
}
/*
* Calculate expected memory requirements for spilling, which is the size
* of the buffers needed for all the tapes that need to be open at
* once. Then, subtract that from the memory available for holding hash
* tables.
*/
npartitions = hash_choose_num_partitions(aggstate,
input_groups,
hashentrysize,
used_bits,
NULL);
if (num_partitions != NULL)
*num_partitions = npartitions;
partition_mem =
HASHAGG_READ_BUFFER_SIZE +
HASHAGG_WRITE_BUFFER_SIZE * npartitions;
/*
* Don't set the limit below 3/4 of work_mem. In that case, we are at the
* minimum number of partitions, so we aren't going to dramatically exceed
* work mem anyway.
*/
if (strict_memlimit * 1024L > 4 * partition_mem)
*mem_limit = strict_memlimit * 1024L - partition_mem;
else
*mem_limit = strict_memlimit * 1024L * 0.75;
if (*mem_limit > hashentrysize)
*ngroups_limit = *mem_limit / hashentrysize;
else
*ngroups_limit = 1;
}
/*
* hash_agg_check_limits
*
* After adding a new group to the hash table, check whether we need to enter
* spill mode. Allocations may happen without adding new groups (for instance,
* if the transition state size grows), so this check is imperfect.
*/
static void
hash_agg_check_limits(AggState *aggstate)
{
uint64 ngroups = aggstate->hash_ngroups_current;
Size meta_mem = MemoryContextMemAllocated(
aggstate->hash_metacxt, true);
Size hash_mem = MemoryContextMemAllocated(
aggstate->hashcontext->ecxt_per_tuple_memory, true);
/*
* Don't spill unless there's at least one group in the hash table so we
* can be sure to make progress even in edge cases.
*/
if (aggstate->hash_ngroups_current > 0 &&
(meta_mem + hash_mem > aggstate->hash_mem_limit ||
ngroups > aggstate->hash_ngroups_limit))
{
hash_agg_enter_spill_mode(aggstate);
}
}
/*
* Enter "spill mode", meaning that no new groups are added to any of the hash
* tables. Tuples that would create a new group are instead spilled, and
* processed later.
*/
static void
hash_agg_enter_spill_mode(AggState *aggstate)
{
aggstate->hash_spill_mode = true;
hashagg_recompile_expressions(aggstate, aggstate->table_filled, true);
if (!aggstate->hash_ever_spilled)
{
Assert(aggstate->hash_tapeinfo == NULL);
Assert(aggstate->hash_spills == NULL);
aggstate->hash_ever_spilled = true;
hashagg_tapeinfo_init(aggstate);
aggstate->hash_spills = palloc(
sizeof(HashAggSpill) * aggstate->num_hashes);
for (int setno = 0; setno < aggstate->num_hashes; setno++)
{
AggStatePerHash perhash = &aggstate->perhash[setno];
HashAggSpill *spill = &aggstate->hash_spills[setno];
hashagg_spill_init(aggstate, spill, aggstate->hash_tapeinfo, 0,
perhash->aggnode->numGroups,
aggstate->hashentrysize);
}
if (aggstate->ss.ps.instrument)
{
aggstate->ss.ps.instrument->workfileCreated = true;
}
}
}
/*
* Update metrics after filling the hash table.
*
* If reading from the outer plan, from_tape should be false; if reading from
* another tape, from_tape should be true.
*/
static void
hash_agg_update_metrics(AggState *aggstate, bool from_tape, int npartitions)
{
Size meta_mem;
Size hash_mem;
Size buffer_mem;
Size total_mem;
if (aggstate->aggstrategy != AGG_MIXED &&
aggstate->aggstrategy != AGG_HASHED)
return;
/* memory for the hash table itself */
meta_mem = MemoryContextMemAllocated(aggstate->hash_metacxt, true);
/* memory for the group keys and transition states */
hash_mem = MemoryContextMemAllocated(
aggstate->hashcontext->ecxt_per_tuple_memory, true);
/* memory for read/write tape buffers, if spilled */
buffer_mem = npartitions * HASHAGG_WRITE_BUFFER_SIZE;
if (from_tape)
buffer_mem += HASHAGG_READ_BUFFER_SIZE;
/* update peak mem */
total_mem = meta_mem + hash_mem + buffer_mem;
if (total_mem > aggstate->hash_mem_peak)
aggstate->hash_mem_peak = total_mem;
/* update disk usage */
if (aggstate->hash_tapeinfo != NULL)
{
uint64 disk_used = LogicalTapeSetBlocks(
aggstate->hash_tapeinfo->tapeset) * (BLCKSZ / 1024);
if (aggstate->hash_disk_used < disk_used)
aggstate->hash_disk_used = disk_used;
}
/* update hashentrysize estimate based on contents */
if (aggstate->hash_ngroups_current > 0)
{
aggstate->hashentrysize =
sizeof(TupleHashEntryData) +
(hash_mem / (double)aggstate->hash_ngroups_current);
}
if (aggstate->ss.ps.instrument && aggstate->ss.ps.instrument->need_cdb)
{
Instrumentation *instrument = aggstate->ss.ps.instrument;
instrument->workmemused = aggstate->hash_mem_peak;
}
}
/*
* Choose a reasonable number of buckets for the initial hash table size.
*/
static long
hash_choose_num_buckets(double hashentrysize, long ngroups, Size memory)
{
long max_nbuckets;
long nbuckets = ngroups;
max_nbuckets = memory / hashentrysize;
/*
* Underestimating is better than overestimating. Too many buckets crowd
* out space for group keys and transition state values.
*/
max_nbuckets >>= 1;
if (nbuckets > max_nbuckets)
nbuckets = max_nbuckets;
return Max(nbuckets, 1);
}
/*
* Determine the number of partitions to create when spilling, which will
* always be a power of two. If log2_npartitions is non-NULL, set
* *log2_npartitions to the log2() of the number of partitions.
*/
static int
hash_choose_num_partitions(AggState *aggstate, uint64 input_groups, double hashentrysize,
int used_bits, int *log2_npartitions)
{
Size mem_wanted;
int partition_limit;
int npartitions;
int partition_bits;
uint64 strict_memlimit = work_mem;
if (aggstate)
{
uint64 operator_mem = PlanStateOperatorMemKB((PlanState *) aggstate);
if (operator_mem < strict_memlimit)
strict_memlimit = operator_mem;
}
/*
* Avoid creating so many partitions that the memory requirements of the
* open partition files are greater than 1/4 of work_mem.
*/
partition_limit =
(strict_memlimit * 1024L * 0.25 - HASHAGG_READ_BUFFER_SIZE) /
HASHAGG_WRITE_BUFFER_SIZE;
mem_wanted = HASHAGG_PARTITION_FACTOR * input_groups * hashentrysize;
/* make enough partitions so that each one is likely to fit in memory */
npartitions = 1 + (mem_wanted / (strict_memlimit * 1024L));
if (npartitions > partition_limit)
npartitions = partition_limit;
if (npartitions < HASHAGG_MIN_PARTITIONS)
npartitions = HASHAGG_MIN_PARTITIONS;
if (npartitions > HASHAGG_MAX_PARTITIONS)
npartitions = HASHAGG_MAX_PARTITIONS;
/* ceil(log2(npartitions)) */
partition_bits = my_log2(npartitions);
/* make sure that we don't exhaust the hash bits */
if (partition_bits + used_bits >= 32)
partition_bits = 32 - used_bits;
if (log2_npartitions != NULL)
*log2_npartitions = partition_bits;
/* number of partitions will be a power of two */
npartitions = 1L << partition_bits;
return npartitions;
}
/*
* Find or create a hashtable entry for the tuple group containing the current
* tuple (already set in tmpcontext's outertuple slot), in the current grouping
* set (which the caller must have selected - note that initialize_aggregate
* depends on this).
*
* When called, CurrentMemoryContext should be the per-query context. The
* already-calculated hash value for the tuple must be specified.
*
* If in "spill mode", then only find existing hashtable entries; don't create
* new ones. If a tuple's group is not already present in the hash table for
* the current grouping set, assign *in_hash_table=false and the caller will
* spill it to disk.
*/
static AggStatePerGroup
lookup_hash_entry(AggState *aggstate, uint32 hash, bool *in_hash_table)
{
AggStatePerHash perhash = &aggstate->perhash[aggstate->current_set];
TupleTableSlot *hashslot = perhash->hashslot;
TupleHashEntryData *entry;
bool isnew = false;
bool *p_isnew;
/* if hash table already spilled, don't create new entries */
p_isnew = aggstate->hash_spill_mode ? NULL : &isnew;
/* find or create the hashtable entry using the filtered tuple */
entry = LookupTupleHashEntryHash(perhash->hashtable, hashslot, p_isnew,
hash);
if (entry == NULL)
{
*in_hash_table = false;
return NULL;
}
else
*in_hash_table = true;
if (isnew)
{
AggStatePerGroup pergroup;
int transno;
aggstate->hash_ngroups_current++;
hash_agg_check_limits(aggstate);
/* no need to allocate or initialize per-group state */
if (aggstate->numtrans == 0)
return NULL;
pergroup = (AggStatePerGroup)
MemoryContextAlloc(perhash->hashtable->tablecxt,
sizeof(AggStatePerGroupData) * aggstate->numtrans);
entry->additional = pergroup;
/*
* Initialize aggregates for new tuple group, lookup_hash_entries()
* already has selected the relevant grouping set.
*/
for (transno = 0; transno < aggstate->numtrans; transno++)
{
AggStatePerTrans pertrans = &aggstate->pertrans[transno];
AggStatePerGroup pergroupstate = &pergroup[transno];
initialize_aggregate(aggstate, pertrans, pergroupstate);
}
}
return entry->additional;
}
/*
* Look up hash entries for the current tuple in all hashed grouping sets,
* returning an array of pergroup pointers suitable for advance_aggregates.
*
* Be aware that lookup_hash_entry can reset the tmpcontext.
*
* Some entries may be left NULL if we are in "spill mode". The same tuple
* will belong to different groups for each grouping set, so may match a group
* already in memory for one set and match a group not in memory for another
* set. When in "spill mode", the tuple will be spilled for each grouping set
* where it doesn't match a group in memory.
*
* NB: It's possible to spill the same tuple for several different grouping
* sets. This may seem wasteful, but it's actually a trade-off: if we spill
* the tuple multiple times for multiple grouping sets, it can be partitioned
* for each grouping set, making the refilling of the hash table very
* efficient.
*/
static void
lookup_hash_entries(AggState *aggstate)
{
AggStatePerGroup *pergroup = aggstate->hash_pergroup;
int setno;
for (setno = 0; setno < aggstate->num_hashes; setno++)
{
AggStatePerHash perhash = &aggstate->perhash[setno];
uint32 hash;
bool in_hash_table;
select_current_set(aggstate, setno, true);
prepare_hash_slot(aggstate);
hash = TupleHashTableHash(perhash->hashtable, perhash->hashslot);
pergroup[setno] = lookup_hash_entry(aggstate, hash, &in_hash_table);
/* check to see if we need to spill the tuple for this grouping set */
if (!in_hash_table)
{
HashAggSpill *spill = &aggstate->hash_spills[setno];
TupleTableSlot *slot = aggstate->tmpcontext->ecxt_outertuple;
if (spill->partitions == NULL)
hashagg_spill_init(aggstate, spill, aggstate->hash_tapeinfo, 0,
perhash->aggnode->numGroups,
aggstate->hashentrysize);
hashagg_spill_tuple(spill, slot, hash);
}
}
}
/*
* ExecAgg -
*
* ExecAgg receives tuples from its outer subplan and aggregates over
* the appropriate attribute for each aggregate function use (Aggref
* node) appearing in the targetlist or qual of the node. The number
* of tuples to aggregate over depends on whether grouped or plain
* aggregation is selected. In grouped aggregation, we produce a result
* row for each group; in plain aggregation there's a single result row
* for the whole query. In either case, the value of each aggregate is
* stored in the expression context to be used when ExecProject evaluates
* the result tuple.
*
* Streaming bottom: forces end of passes when no tuple for underlying node.
*
* MPP-2614: Btree scan will return null tuple at end of scan. However,
* if one calls ExecProNode again on a btree scan, it will restart from
* beginning even though we did not call rescan. This is a bug on
* btree scan, but mask it off here for v3.1. Really should fix Btree
* code.
*/
static TupleTableSlot *
ExecAgg(PlanState *pstate)
{
AggState *node = castNode(AggState, pstate);
TupleTableSlot *result = NULL;
CHECK_FOR_INTERRUPTS();
if (!node->agg_done)
{
/* Dispatch based on strategy */
switch (node->phase->aggstrategy)
{
case AGG_HASHED:
if (!node->table_filled)
agg_fill_hash_table(node);
/* FALLTHROUGH */
case AGG_MIXED:
result = agg_retrieve_hash_table(node);
break;
case AGG_PLAIN:
case AGG_SORTED:
result = agg_retrieve_direct(node);
break;
}
if (!TupIsNull(result))
return result;
}
return NULL;
}
/*
* ExecAgg for non-hashed case
*/
static TupleTableSlot *
agg_retrieve_direct(AggState *aggstate)
{
Agg *node = aggstate->phase->aggnode;
ExprContext *econtext;
ExprContext *tmpcontext;
AggStatePerAgg peragg;
AggStatePerGroup *pergroups;
TupleTableSlot *outerslot;
TupleTableSlot *firstSlot;
TupleTableSlot *result;
bool hasGroupingSets = aggstate->phase->numsets > 0;
int numGroupingSets = Max(aggstate->phase->numsets, 1);
int currentSet;
int nextSetSize;
int numReset;
int i;
/*
* get state info from node
*
* econtext is the per-output-tuple expression context
*
* tmpcontext is the per-input-tuple expression context
*/
econtext = aggstate->ss.ps.ps_ExprContext;
tmpcontext = aggstate->tmpcontext;
peragg = aggstate->peragg;
pergroups = aggstate->pergroups;
firstSlot = aggstate->ss.ss_ScanTupleSlot;
/*
* We loop retrieving groups until we find one matching
* aggstate->ss.ps.qual
*
* For grouping sets, we have the invariant that aggstate->projected_set
* is either -1 (initial call) or the index (starting from 0) in
* gset_lengths for the group we just completed (either by projecting a
* row or by discarding it in the qual).
*/
while (!aggstate->agg_done)
{
/*
* Clear the per-output-tuple context for each group, as well as
* aggcontext (which contains any pass-by-ref transvalues of the old
* group). Some aggregate functions store working state in child
* contexts; those now get reset automatically without us needing to
* do anything special.
*
* We use ReScanExprContext not just ResetExprContext because we want
* any registered shutdown callbacks to be called. That allows
* aggregate functions to ensure they've cleaned up any non-memory
* resources.
*/
ReScanExprContext(econtext);
/*
* Determine how many grouping sets need to be reset at this boundary.
*/
if (aggstate->projected_set >= 0 &&
aggstate->projected_set < numGroupingSets)
numReset = aggstate->projected_set + 1;
else
numReset = numGroupingSets;
/*
* numReset can change on a phase boundary, but that's OK; we want to
* reset the contexts used in _this_ phase, and later, after possibly
* changing phase, initialize the right number of aggregates for the
* _new_ phase.
*/
for (i = 0; i < numReset; i++)
{
ReScanExprContext(aggstate->aggcontexts[i]);
}
/*
* Check if input is complete and there are no more groups to project
* in this phase; move to next phase or mark as done.
*/
if (aggstate->input_done == true &&
aggstate->projected_set >= (numGroupingSets - 1))
{
if (aggstate->current_phase < aggstate->numphases - 1)
{
initialize_phase(aggstate, aggstate->current_phase + 1);
aggstate->input_done = false;
aggstate->projected_set = -1;
numGroupingSets = Max(aggstate->phase->numsets, 1);
node = aggstate->phase->aggnode;
numReset = numGroupingSets;
}
else if (aggstate->aggstrategy == AGG_MIXED)
{
/*
* Mixed mode; we've output all the grouped stuff and have
* full hashtables, so switch to outputting those.
*/
initialize_phase(aggstate, 0);
aggstate->table_filled = true;
ResetTupleHashIterator(aggstate->perhash[0].hashtable,
&aggstate->perhash[0].hashiter);
select_current_set(aggstate, 0, true);
return agg_retrieve_hash_table(aggstate);
}
else
{
aggstate->agg_done = true;
break;
}
}
/*
* Get the number of columns in the next grouping set after the last
* projected one (if any). This is the number of columns to compare to
* see if we reached the boundary of that set too.
*/
if (aggstate->projected_set >= 0 &&
aggstate->projected_set < (numGroupingSets - 1))
nextSetSize = aggstate->phase->gset_lengths[aggstate->projected_set + 1];
else
nextSetSize = 0;
/*----------
* If a subgroup for the current grouping set is present, project it.
*
* We have a new group if:
* - we're out of input but haven't projected all grouping sets
* (checked above)
* OR
* - we already projected a row that wasn't from the last grouping
* set
* AND
* - the next grouping set has at least one grouping column (since
* empty grouping sets project only once input is exhausted)
* AND
* - the previous and pending rows differ on the grouping columns
* of the next grouping set
*----------
*/
tmpcontext->ecxt_innertuple = econtext->ecxt_outertuple;
if (aggstate->input_done ||
(node->aggstrategy != AGG_PLAIN &&
aggstate->projected_set != -1 &&
aggstate->projected_set < (numGroupingSets - 1) &&
nextSetSize > 0 &&
!ExecQualAndReset(aggstate->phase->eqfunctions[nextSetSize - 1],
tmpcontext)))
{
aggstate->projected_set += 1;
Assert(aggstate->projected_set < numGroupingSets);
Assert(nextSetSize > 0 || aggstate->input_done);
}
else
{
/*
* We no longer care what group we just projected, the next
* projection will always be the first (or only) grouping set
* (unless the input proves to be empty).
*/
aggstate->projected_set = 0;
/*
* If we don't already have the first tuple of the new group,
* fetch it from the outer plan.
*/
if (aggstate->grp_firstTuple == NULL)
{
outerslot = fetch_input_tuple(aggstate);
if (!TupIsNull(outerslot))
{
/*
* Make a copy of the first input tuple; we will use this
* for comparisons (in group mode) and for projection.
*/
aggstate->grp_firstTuple = ExecCopySlotHeapTuple(outerslot);
}
else
{
/* outer plan produced no tuples at all */
if (hasGroupingSets)
{
/*
* If there was no input at all, we need to project
* rows only if there are grouping sets of size 0.
* Note that this implies that there can't be any
* references to ungrouped Vars, which would otherwise
* cause issues with the empty output slot.
*
* XXX: This is no longer true, we currently deal with
* this in finalize_aggregates().
*/
aggstate->input_done = true;
while (aggstate->phase->gset_lengths[aggstate->projected_set] > 0)
{
aggstate->projected_set += 1;
if (aggstate->projected_set >= numGroupingSets)
{
/*
* We can't set agg_done here because we might
* have more phases to do, even though the
* input is empty. So we need to restart the
* whole outer loop.
*/
break;
}
}
if (aggstate->projected_set >= numGroupingSets)
continue;
}
else
{
aggstate->agg_done = true;
/* If we are grouping, we should produce no tuples too */
if (node->aggstrategy != AGG_PLAIN)
return NULL;
}
}
}
/*
* Initialize working state for a new input tuple group.
*/
initialize_aggregates(aggstate, pergroups, numReset);
if (aggstate->grp_firstTuple != NULL)
{
/*
* Store the copied first input tuple in the tuple table slot
* reserved for it. The tuple will be deleted when it is
* cleared from the slot.
*/
ExecForceStoreHeapTuple(aggstate->grp_firstTuple,
firstSlot, true);
aggstate->grp_firstTuple = NULL; /* don't keep two pointers */
/* set up for first advance_aggregates call */
tmpcontext->ecxt_outertuple = firstSlot;
/*
* Process each outer-plan tuple, and then fetch the next one,
* until we exhaust the outer plan or cross a group boundary.
*/
for (;;)
{
/*
* During phase 1 only of a mixed agg, we need to update
* hashtables as well in advance_aggregates.
*/
if (aggstate->aggstrategy == AGG_MIXED &&
aggstate->current_phase == 1)
{
lookup_hash_entries(aggstate);
}
/* Advance the aggregates (or combine functions) */
advance_aggregates(aggstate);
/* Reset per-input-tuple context after each tuple */
ResetExprContext(tmpcontext);
outerslot = fetch_input_tuple(aggstate);
if (TupIsNull(outerslot))
{
/* no more outer-plan tuples available */
/* if we built hash tables, finalize any spills */
if (aggstate->aggstrategy == AGG_MIXED &&
aggstate->current_phase == 1)
hashagg_finish_initial_spills(aggstate);
if (hasGroupingSets)
{
aggstate->input_done = true;
break;
}
else
{
aggstate->agg_done = true;
break;
}
}
/* set up for next advance_aggregates call */
tmpcontext->ecxt_outertuple = outerslot;
/*
* If we are grouping, check whether we've crossed a group
* boundary.
*/
if (node->aggstrategy != AGG_PLAIN)
{
tmpcontext->ecxt_innertuple = firstSlot;
if (!ExecQual(aggstate->phase->eqfunctions[node->numCols - 1],
tmpcontext))
{
aggstate->grp_firstTuple = ExecCopySlotHeapTuple(outerslot);
break;
}
}
}
}
/*
* Use the representative input tuple for any references to
* non-aggregated input columns in aggregate direct args, the node
* qual, and the tlist. (If we are not grouping, and there are no
* input rows at all, we will come here with an empty firstSlot
* ... but if not grouping, there can't be any references to
* non-aggregated input columns, so no problem.)
*/
econtext->ecxt_outertuple = firstSlot;
}
Assert(aggstate->projected_set >= 0);
currentSet = aggstate->projected_set;
prepare_projection_slot(aggstate, econtext->ecxt_outertuple, currentSet);
select_current_set(aggstate, currentSet, false);
finalize_aggregates(aggstate,
peragg,
pergroups[currentSet]);
/*
* If there's no row to project right now, we must continue rather
* than returning a null since there might be more groups.
*/
result = project_aggregates(aggstate);
if (result)
return result;
}
/* No more groups */
return NULL;
}
/*
* ExecAgg for hashed case: read input and build hash table
*/
static void
agg_fill_hash_table(AggState *aggstate)
{
TupleTableSlot *outerslot;
ExprContext *tmpcontext = aggstate->tmpcontext;
/*
* Process each outer-plan tuple, and then fetch the next one, until we
* exhaust the outer plan.
*/
for (;;)
{
outerslot = fetch_input_tuple(aggstate);
if (TupIsNull(outerslot))
break;
/* set up for lookup_hash_entries and advance_aggregates */
tmpcontext->ecxt_outertuple = outerslot;
/* Find or build hashtable entries */
lookup_hash_entries(aggstate);
/* Advance the aggregates (or combine functions) */
advance_aggregates(aggstate);
/*
* Reset per-input-tuple context after each tuple, but note that the
* hash lookups do this too
*/
ResetExprContext(aggstate->tmpcontext);
}
/* finalize spills, if any */
hashagg_finish_initial_spills(aggstate);
aggstate->table_filled = true;
/* Initialize to walk the first hash table */
select_current_set(aggstate, 0, true);
ResetTupleHashIterator(aggstate->perhash[0].hashtable,
&aggstate->perhash[0].hashiter);
}
/*
* If any data was spilled during hash aggregation, reset the hash table and
* reprocess one batch of spilled data. After reprocessing a batch, the hash
* table will again contain data, ready to be consumed by
* agg_retrieve_hash_table_in_memory().
*
* Should only be called after all in memory hash table entries have been
* finalized and emitted.
*
* Return false when input is exhausted and there's no more work to be done;
* otherwise return true.
*/
static bool
agg_refill_hash_table(AggState *aggstate)
{
HashAggBatch *batch;
HashAggSpill spill;
HashTapeInfo *tapeinfo = aggstate->hash_tapeinfo;
uint64 ngroups_estimate;
bool spill_initialized = false;
if (aggstate->hash_batches == NIL)
return false;
batch = linitial(aggstate->hash_batches);
aggstate->hash_batches = list_delete_first(aggstate->hash_batches);
/*
* Estimate the number of groups for this batch as the total number of
* tuples in its input file. Although that's a worst case, it's not bad
* here for two reasons: (1) overestimating is better than
* underestimating; and (2) we've already scanned the relation once, so
* it's likely that we've already finalized many of the common values.
*/
ngroups_estimate = batch->input_tuples;
hash_agg_set_limits(aggstate, aggstate->hashentrysize, ngroups_estimate,
batch->used_bits, &aggstate->hash_mem_limit,
&aggstate->hash_ngroups_limit, NULL);
/* there could be residual pergroup pointers; clear them */
for (int setoff = 0;
setoff < aggstate->maxsets + aggstate->num_hashes;
setoff++)
aggstate->all_pergroups[setoff] = NULL;
/* free memory and reset hash tables */
ReScanExprContext(aggstate->hashcontext);
for (int setno = 0; setno < aggstate->num_hashes; setno++)
ResetTupleHashTable(aggstate->perhash[setno].hashtable);
aggstate->hash_ngroups_current = 0;
/*
* In AGG_MIXED mode, hash aggregation happens in phase 1 and the output
* happens in phase 0. So, we switch to phase 1 when processing a batch,
* and back to phase 0 after the batch is done.
*/
Assert(aggstate->current_phase == 0);
if (aggstate->phase->aggstrategy == AGG_MIXED)
{
aggstate->current_phase = 1;
aggstate->phase = &aggstate->phases[aggstate->current_phase];
}
select_current_set(aggstate, batch->setno, true);
/*
* Spilled tuples are always read back as MinimalTuples, which may be
* different from the outer plan, so recompile the aggregate expressions.
*
* We still need the NULL check, because we are only processing one
* grouping set at a time and the rest will be NULL.
*/
hashagg_recompile_expressions(aggstate, true, true);
LogicalTapeRewindForRead(tapeinfo->tapeset, batch->input_tapenum,
HASHAGG_READ_BUFFER_SIZE);
for (;;) {
TupleTableSlot *slot = aggstate->hash_spill_slot;
MinimalTuple tuple;
uint32 hash;
bool in_hash_table;
CHECK_FOR_INTERRUPTS();
tuple = hashagg_batch_read(batch, &hash);
if (tuple == NULL)
break;
ExecStoreMinimalTuple(tuple, slot, true);
aggstate->tmpcontext->ecxt_outertuple = slot;
prepare_hash_slot(aggstate);
aggstate->hash_pergroup[batch->setno] = lookup_hash_entry(
aggstate, hash, &in_hash_table);
if (in_hash_table)
{
/* Advance the aggregates (or combine functions) */
advance_aggregates(aggstate);
}
else
{
if (!spill_initialized)
{
/*
* Avoid initializing the spill until we actually need it so
* that we don't assign tapes that will never be used.
*/
spill_initialized = true;
hashagg_spill_init(aggstate, &spill, tapeinfo, batch->used_bits,
ngroups_estimate, aggstate->hashentrysize);
}
/* no memory for a new group, spill */
hashagg_spill_tuple(&spill, slot, hash);
}
/*
* Reset per-input-tuple context after each tuple, but note that the
* hash lookups do this too
*/
ResetExprContext(aggstate->tmpcontext);
}
hashagg_tapeinfo_release(tapeinfo, batch->input_tapenum);
/* change back to phase 0 */
aggstate->current_phase = 0;
aggstate->phase = &aggstate->phases[aggstate->current_phase];
if (spill_initialized)
{
hash_agg_update_metrics(aggstate, true, spill.npartitions);
hashagg_spill_finish(aggstate, &spill, batch->setno);
}
else
hash_agg_update_metrics(aggstate, true, 0);
aggstate->hash_spill_mode = false;
/* prepare to walk the first hash table */
select_current_set(aggstate, batch->setno, true);
ResetTupleHashIterator(aggstate->perhash[batch->setno].hashtable,
&aggstate->perhash[batch->setno].hashiter);
pfree(batch);
return true;
}
/*
* ExecAgg for hashed case: retrieving groups from hash table
*
* After exhausting in-memory tuples, also try refilling the hash table using
* previously-spilled tuples. Only returns NULL after all in-memory and
* spilled tuples are exhausted.
*/
static TupleTableSlot *
agg_retrieve_hash_table(AggState *aggstate)
{
TupleTableSlot *result = NULL;
while (result == NULL)
{
result = agg_retrieve_hash_table_in_memory(aggstate);
if (result == NULL)
{
if (!agg_refill_hash_table(aggstate))
{
aggstate->agg_done = true;
break;
}
}
}
return result;
}
/*
* Retrieve the groups from the in-memory hash tables without considering any
* spilled tuples.
*/
static TupleTableSlot *
agg_retrieve_hash_table_in_memory(AggState *aggstate)
{
ExprContext *econtext;
AggStatePerAgg peragg;
AggStatePerGroup pergroup;
TupleHashEntryData *entry;
TupleTableSlot *firstSlot;
TupleTableSlot *result;
AggStatePerHash perhash;
/*
* get state info from node.
*
* econtext is the per-output-tuple expression context.
*/
econtext = aggstate->ss.ps.ps_ExprContext;
peragg = aggstate->peragg;
firstSlot = aggstate->ss.ss_ScanTupleSlot;
/*
* Note that perhash (and therefore anything accessed through it) can
* change inside the loop, as we change between grouping sets.
*/
perhash = &aggstate->perhash[aggstate->current_set];
/*
* We loop retrieving groups until we find one satisfying
* aggstate->ss.ps.qual
*/
for (;;)
{
TupleTableSlot *hashslot = perhash->hashslot;
int i;
CHECK_FOR_INTERRUPTS();
/*
* Find the next entry in the hash table
*/
entry = ScanTupleHashTable(perhash->hashtable, &perhash->hashiter);
if (entry == NULL)
{
int nextset = aggstate->current_set + 1;
if (nextset < aggstate->num_hashes)
{
/*
* Switch to next grouping set, reinitialize, and restart the
* loop.
*/
select_current_set(aggstate, nextset, true);
perhash = &aggstate->perhash[aggstate->current_set];
ResetTupleHashIterator(perhash->hashtable, &perhash->hashiter);
continue;
}
else
{
return NULL;
}
}
/*
* Clear the per-output-tuple context for each group
*
* We intentionally don't use ReScanExprContext here; if any aggs have
* registered shutdown callbacks, they mustn't be called yet, since we
* might not be done with that agg.
*/
ResetExprContext(econtext);
/*
* Transform representative tuple back into one with the right
* columns.
*/
ExecStoreMinimalTuple(entry->firstTuple, hashslot, false);
slot_getallattrs(hashslot);
ExecClearTuple(firstSlot);
memset(firstSlot->tts_isnull, true,
firstSlot->tts_tupleDescriptor->natts * sizeof(bool));
for (i = 0; i < perhash->numhashGrpCols; i++)
{
int varNumber = perhash->hashGrpColIdxInput[i] - 1;
firstSlot->tts_values[varNumber] = hashslot->tts_values[i];
firstSlot->tts_isnull[varNumber] = hashslot->tts_isnull[i];
}
ExecStoreVirtualTuple(firstSlot);
pergroup = (AggStatePerGroup) entry->additional;
/*
* Use the representative input tuple for any references to
* non-aggregated input columns in the qual and tlist.
*/
econtext->ecxt_outertuple = firstSlot;
prepare_projection_slot(aggstate,
econtext->ecxt_outertuple,
aggstate->current_set);
finalize_aggregates(aggstate, peragg, pergroup);
result = project_aggregates(aggstate);
if (result)
return result;
}
/* No more groups */
return NULL;
}
/*
* Initialize HashTapeInfo
*/
static void
hashagg_tapeinfo_init(AggState *aggstate)
{
HashTapeInfo *tapeinfo = palloc(sizeof(HashTapeInfo));
int init_tapes = 16; /* expanded dynamically */
tapeinfo->tapeset = LogicalTapeSetCreate(init_tapes, NULL, NULL, -1);
tapeinfo->ntapes = init_tapes;
tapeinfo->nfreetapes = init_tapes;
tapeinfo->freetapes_alloc = init_tapes;
tapeinfo->freetapes = palloc(init_tapes * sizeof(int));
for (int i = 0; i < init_tapes; i++)
tapeinfo->freetapes[i] = i;
aggstate->hash_tapeinfo = tapeinfo;
#ifdef FAULT_INJECTOR
if (SIMPLE_FAULT_INJECTOR("hashagg_spill_temp_files") == FaultInjectorTypeSkip) {
const char *filename = LogicalTapeGetBufFilename(tapeinfo->tapeset);
if (!filename)
ereport(NOTICE, (errmsg("hashagg: buffilename is null")));
else if (strstr(filename, "base/" PG_TEMP_FILES_DIR) == filename)
ereport(NOTICE, (errmsg("hashagg: Use default tablespace")));
else if (strstr(filename, "pg_tblspc/") == filename)
ereport(NOTICE, (errmsg("hashagg: Use temp tablespace")));
else
ereport(NOTICE, (errmsg("hashagg: Unexpected prefix of the tablespace path")));
}
#endif
}
/*
* Assign unused tapes to spill partitions, extending the tape set if
* necessary.
*/
static void
hashagg_tapeinfo_assign(HashTapeInfo *tapeinfo, int *partitions,
int npartitions)
{
int partidx = 0;
/* use free tapes if available */
while (partidx < npartitions && tapeinfo->nfreetapes > 0)
partitions[partidx++] = tapeinfo->freetapes[--tapeinfo->nfreetapes];
if (partidx < npartitions)
{
LogicalTapeSetExtend(tapeinfo->tapeset, npartitions - partidx);
while (partidx < npartitions)
partitions[partidx++] = tapeinfo->ntapes++;
}
}
/*
* After a tape has already been written to and then read, this function
* rewinds it for writing and adds it to the free list.
*/
static void
hashagg_tapeinfo_release(HashTapeInfo *tapeinfo, int tapenum)
{
LogicalTapeRewindForWrite(tapeinfo->tapeset, tapenum);
if (tapeinfo->freetapes_alloc == tapeinfo->nfreetapes)
{
tapeinfo->freetapes_alloc <<= 1;
tapeinfo->freetapes = repalloc(
tapeinfo->freetapes, tapeinfo->freetapes_alloc * sizeof(int));
}
tapeinfo->freetapes[tapeinfo->nfreetapes++] = tapenum;
}
/*
* hashagg_spill_init
*
* Called after we determined that spilling is necessary. Chooses the number
* of partitions to create, and initializes them.
*/
static void
hashagg_spill_init(AggState *aggstate, HashAggSpill *spill, HashTapeInfo *tapeinfo, int used_bits,
uint64 input_groups, double hashentrysize)
{
int npartitions;
int partition_bits;
npartitions = hash_choose_num_partitions(aggstate,
input_groups, hashentrysize, used_bits, &partition_bits);
spill->partitions = palloc0(sizeof(int) * npartitions);
spill->ntuples = palloc0(sizeof(int64) * npartitions);
hashagg_tapeinfo_assign(tapeinfo, spill->partitions, npartitions);
spill->tapeset = tapeinfo->tapeset;
spill->shift = 32 - used_bits - partition_bits;
spill->mask = (npartitions - 1) << spill->shift;
spill->npartitions = npartitions;
}
/*
* hashagg_spill_tuple
*
* No room for new groups in the hash table. Save for later in the appropriate
* partition.
*/
static Size
hashagg_spill_tuple(HashAggSpill *spill, TupleTableSlot *slot, uint32 hash)
{
LogicalTapeSet *tapeset = spill->tapeset;
int partition;
MinimalTuple tuple;
int tapenum;
int total_written = 0;
bool shouldFree;
Assert(spill->partitions != NULL);
/* XXX: may contain unnecessary attributes, should project */
tuple = ExecFetchSlotMinimalTuple(slot, &shouldFree);
partition = (hash & spill->mask) >> spill->shift;
spill->ntuples[partition]++;
tapenum = spill->partitions[partition];
LogicalTapeWrite(tapeset, tapenum, (void *) &hash, sizeof(uint32));
total_written += sizeof(uint32);
LogicalTapeWrite(tapeset, tapenum, (void *) tuple, tuple->t_len);
total_written += tuple->t_len;
if (shouldFree)
pfree(tuple);
return total_written;
}
/*
* hashagg_batch_new
*
* Construct a HashAggBatch item, which represents one iteration of HashAgg to
* be done.
*/
static HashAggBatch *
hashagg_batch_new(LogicalTapeSet *tapeset, int tapenum, int setno,
int64 input_tuples, int used_bits)
{
HashAggBatch *batch = palloc0(sizeof(HashAggBatch));
batch->setno = setno;
batch->used_bits = used_bits;
batch->tapeset = tapeset;
batch->input_tapenum = tapenum;
batch->input_tuples = input_tuples;
return batch;
}
/*
* read_spilled_tuple
* read the next tuple from a batch's tape. Return NULL if no more.
*/
static MinimalTuple
hashagg_batch_read(HashAggBatch *batch, uint32 *hashp)
{
LogicalTapeSet *tapeset = batch->tapeset;
int tapenum = batch->input_tapenum;
MinimalTuple tuple;
uint32 t_len;
size_t nread;
uint32 hash;
nread = LogicalTapeRead(tapeset, tapenum, &hash, sizeof(uint32));
if (nread == 0)
return NULL;
if (nread != sizeof(uint32))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("unexpected EOF for tape %d: requested %zu bytes, read %zu bytes",
tapenum, sizeof(uint32), nread)));
if (hashp != NULL)
*hashp = hash;
nread = LogicalTapeRead(tapeset, tapenum, &t_len, sizeof(t_len));
if (nread != sizeof(uint32))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("unexpected EOF for tape %d: requested %zu bytes, read %zu bytes",
tapenum, sizeof(uint32), nread)));
tuple = (MinimalTuple) palloc(t_len);
tuple->t_len = t_len;
nread = LogicalTapeRead(tapeset, tapenum,
(void *)((char *)tuple + sizeof(uint32)),
t_len - sizeof(uint32));
if (nread != t_len - sizeof(uint32))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("unexpected EOF for tape %d: requested %zu bytes, read %zu bytes",
tapenum, t_len - sizeof(uint32), nread)));
return tuple;
}
/*
* hashagg_finish_initial_spills
*
* After a HashAggBatch has been processed, it may have spilled tuples to
* disk. If so, turn the spilled partitions into new batches that must later
* be executed.
*/
static void
hashagg_finish_initial_spills(AggState *aggstate)
{
int setno;
int total_npartitions = 0;
if (aggstate->hash_spills != NULL)
{
for (setno = 0; setno < aggstate->num_hashes; setno++)
{
HashAggSpill *spill = &aggstate->hash_spills[setno];
total_npartitions += spill->npartitions;
hashagg_spill_finish(aggstate, spill, setno);
}
/*
* We're not processing tuples from outer plan any more; only
* processing batches of spilled tuples. The initial spill structures
* are no longer needed.
*/
pfree(aggstate->hash_spills);
aggstate->hash_spills = NULL;
}
hash_agg_update_metrics(aggstate, false, total_npartitions);
aggstate->hash_spill_mode = false;
}
/*
* hashagg_spill_finish
*
* Transform spill partitions into new batches.
*/
static void
hashagg_spill_finish(AggState *aggstate, HashAggSpill *spill, int setno)
{
int i;
int used_bits = 32 - spill->shift;
if (spill->npartitions == 0)
return; /* didn't spill */
for (i = 0; i < spill->npartitions; i++)
{
int tapenum = spill->partitions[i];
HashAggBatch *new_batch;
/* if the partition is empty, don't create a new batch of work */
if (spill->ntuples[i] == 0)
continue;
new_batch = hashagg_batch_new(aggstate->hash_tapeinfo->tapeset,
tapenum, setno, spill->ntuples[i],
used_bits);
aggstate->hash_batches = lcons(new_batch, aggstate->hash_batches);
aggstate->hash_batches_used++;
}
pfree(spill->ntuples);
pfree(spill->partitions);
}
/*
* Free resources related to a spilled HashAgg.
*/
static void
hashagg_reset_spill_state(AggState *aggstate)
{
ListCell *lc;
/* free spills from initial pass */
if (aggstate->hash_spills != NULL)
{
int setno;
for (setno = 0; setno < aggstate->num_hashes; setno++)
{
HashAggSpill *spill = &aggstate->hash_spills[setno];
pfree(spill->ntuples);
pfree(spill->partitions);
}
pfree(aggstate->hash_spills);
aggstate->hash_spills = NULL;
}
/* free batches */
foreach(lc, aggstate->hash_batches)
{
HashAggBatch *batch = (HashAggBatch*) lfirst(lc);
pfree(batch);
}
list_free(aggstate->hash_batches);
aggstate->hash_batches = NIL;
/* close tape set */
if (aggstate->hash_tapeinfo != NULL)
{
HashTapeInfo *tapeinfo = aggstate->hash_tapeinfo;
LogicalTapeSetClose(tapeinfo->tapeset);
pfree(tapeinfo->freetapes);
pfree(tapeinfo);
aggstate->hash_tapeinfo = NULL;
}
}
/* -----------------
* ExecInitAgg
*
* Creates the run-time information for the agg node produced by the
* planner and initializes its outer subtree.
*
* -----------------
*/
AggState *
ExecInitAgg(Agg *node, EState *estate, int eflags)
{
AggState *aggstate;
AggStatePerAgg peraggs;
AggStatePerTrans pertransstates;
AggStatePerGroup *pergroups;
Plan *outerPlan;
ExprContext *econtext;
TupleDesc scanDesc;
int numaggs,
transno,
aggno;
int phase;
int phaseidx;
ListCell *l;
Bitmapset *all_grouped_cols = NULL;
int numGroupingSets = 1;
int numPhases;
int numHashes;
int i = 0;
int j = 0;
bool use_hashing = (node->aggstrategy == AGG_HASHED ||
node->aggstrategy == AGG_MIXED);
int numgsets = 0;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
/*
* create state structure
*/
aggstate = makeNode(AggState);
aggstate->ss.ps.plan = (Plan *) node;
aggstate->ss.ps.state = estate;
aggstate->ss.ps.ExecProcNode = ExecAgg;
aggstate->aggs = NIL;
aggstate->numaggs = 0;
aggstate->numtrans = 0;
aggstate->aggstrategy = node->aggstrategy;
aggstate->aggsplit = node->aggsplit;
aggstate->maxsets = 0;
aggstate->projected_set = -1;
aggstate->current_set = 0;
aggstate->peragg = NULL;
aggstate->pertrans = NULL;
aggstate->curperagg = NULL;
aggstate->curpertrans = NULL;
aggstate->input_done = false;
aggstate->agg_done = false;
aggstate->pergroups = NULL;
aggstate->grp_firstTuple = NULL;
aggstate->sort_in = NULL;
aggstate->sort_out = NULL;
/*
* phases[0] always exists, but is dummy in sorted/plain mode
*/
numPhases = (use_hashing ? 1 : 2);
numHashes = (use_hashing ? 1 : 0);
/*
* Calculate the maximum number of grouping sets in any phase; this
* determines the size of some allocations. Also calculate the number of
* phases, since all hashed/mixed nodes contribute to only a single phase.
*/
if (node->groupingSets)
{
numGroupingSets = list_length(node->groupingSets);
foreach(l, node->chain)
{
Agg *agg = lfirst(l);
numGroupingSets = Max(numGroupingSets,
list_length(agg->groupingSets));
/*
* additional AGG_HASHED aggs become part of phase 0, but all
* others add an extra phase.
*/
if (agg->aggstrategy != AGG_HASHED)
++numPhases;
else
++numHashes;
}
}
aggstate->maxsets = numGroupingSets;
aggstate->numphases = numPhases;
aggstate->aggcontexts = (ExprContext **)
palloc0(sizeof(ExprContext *) * numGroupingSets);
/*
* Create expression contexts. We need three or more, one for
* per-input-tuple processing, one for per-output-tuple processing, one
* for all the hashtables, and one for each grouping set. The per-tuple
* memory context of the per-grouping-set ExprContexts (aggcontexts)
* replaces the standalone memory context formerly used to hold transition
* values. We cheat a little by using ExecAssignExprContext() to build
* all of them.
*
* NOTE: the details of what is stored in aggcontexts and what is stored
* in the regular per-query memory context are driven by a simple
* decision: we want to reset the aggcontext at group boundaries (if not
* hashing) and in ExecReScanAgg to recover no-longer-wanted space.
*/
ExecAssignExprContext(estate, &aggstate->ss.ps);
aggstate->tmpcontext = aggstate->ss.ps.ps_ExprContext;
for (i = 0; i < numGroupingSets; ++i)
{
ExecAssignExprContext(estate, &aggstate->ss.ps);
aggstate->aggcontexts[i] = aggstate->ss.ps.ps_ExprContext;
}
if (use_hashing)
aggstate->hashcontext = CreateWorkExprContext(estate);
ExecAssignExprContext(estate, &aggstate->ss.ps);
/*
* Initialize child nodes.
*
* If we are doing a hashed aggregation then the child plan does not need
* to handle REWIND efficiently; see ExecReScanAgg.
*/
if (node->aggstrategy == AGG_HASHED)
eflags &= ~EXEC_FLAG_REWIND;
outerPlan = outerPlan(node);
outerPlanState(aggstate) = ExecInitNode(outerPlan, estate, eflags);
/*
* initialize source tuple type.
*/
aggstate->ss.ps.outerops =
ExecGetResultSlotOps(outerPlanState(&aggstate->ss),
&aggstate->ss.ps.outeropsfixed);
aggstate->ss.ps.outeropsset = true;
ExecCreateScanSlotFromOuterPlan(estate, &aggstate->ss,
aggstate->ss.ps.outerops);
scanDesc = aggstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor;
/*
* If there are more than two phases (including a potential dummy phase
* 0), input will be resorted using tuplesort. Need a slot for that.
*/
if (numPhases > 2)
{
aggstate->sort_slot = ExecInitExtraTupleSlot(estate, scanDesc,
&TTSOpsMinimalTuple);
/*
* The output of the tuplesort, and the output from the outer child
* might not use the same type of slot. In most cases the child will
* be a Sort, and thus return a TTSOpsMinimalTuple type slot - but the
* input can also be be presorted due an index, in which case it could
* be a different type of slot.
*
* XXX: For efficiency it would be good to instead/additionally
* generate expressions with corresponding settings of outerops* for
* the individual phases - deforming is often a bottleneck for
* aggregations with lots of rows per group. If there's multiple
* sorts, we know that all but the first use TTSOpsMinimalTuple (via
* the nodeAgg.c internal tuplesort).
*/
if (aggstate->ss.ps.outeropsfixed &&
aggstate->ss.ps.outerops != &TTSOpsMinimalTuple)
aggstate->ss.ps.outeropsfixed = false;
}
/*
* Initialize result type, slot and projection.
*/
ExecInitResultTupleSlotTL(&aggstate->ss.ps, &TTSOpsVirtual);
ExecAssignProjectionInfo(&aggstate->ss.ps, NULL);
/*
* CDB: Offer extra info for EXPLAIN ANALYZE.
*/
if (estate->es_instrument && (estate->es_instrument & INSTRUMENT_CDB))
{
/* Allocate string buffer. */
aggstate->ss.ps.cdbexplainbuf = makeStringInfo();
}
/*
* initialize child expressions
*
* We expect the parser to have checked that no aggs contain other agg
* calls in their arguments (and just to be sure, we verify it again while
* initializing the plan node). This would make no sense under SQL
* semantics, and it's forbidden by the spec. Because it is true, we
* don't need to worry about evaluating the aggs in any particular order.
*
* Note: execExpr.c finds Aggrefs for us, and adds their AggrefExprState
* nodes to aggstate->aggs. Aggrefs in the qual are found here; Aggrefs
* in the targetlist are found during ExecAssignProjectionInfo, below.
*/
aggstate->ss.ps.qual =
ExecInitQual(node->plan.qual, (PlanState *) aggstate);
/*
* We should now have found all Aggrefs in the targetlist and quals.
*/
numaggs = aggstate->numaggs;
Assert(numaggs == list_length(aggstate->aggs));
/*
* For each phase, prepare grouping set data and fmgr lookup data for
* compare functions. Accumulate all_grouped_cols in passing.
*/
aggstate->phases = palloc0(numPhases * sizeof(AggStatePerPhaseData));
aggstate->num_hashes = numHashes;
if (numHashes)
{
aggstate->perhash = palloc0(sizeof(AggStatePerHashData) * numHashes);
aggstate->phases[0].numsets = 0;
aggstate->phases[0].gset_lengths = palloc(numHashes * sizeof(int));
aggstate->phases[0].grouped_cols = palloc(numHashes * sizeof(Bitmapset *));
aggstate->phases[0].gset_id = palloc(numHashes * sizeof(int));
aggstate->phases[0].group_id = palloc0(numHashes * sizeof(int));
}
phase = 0;
for (phaseidx = 0; phaseidx <= list_length(node->chain); ++phaseidx)
{
Agg *aggnode;
Sort *sortnode;
if (phaseidx > 0)
{
aggnode = list_nth_node(Agg, node->chain, phaseidx - 1);
sortnode = castNode(Sort, aggnode->plan.lefttree);
}
else
{
aggnode = node;
sortnode = NULL;
}
Assert(phase <= 1 || sortnode);
if (aggnode->aggstrategy == AGG_HASHED
|| aggnode->aggstrategy == AGG_MIXED)
{
AggStatePerPhase phasedata = &aggstate->phases[0];
AggStatePerHash perhash;
Bitmapset *cols = NULL;
Assert(phase == 0);
i = phasedata->numsets++;
perhash = &aggstate->perhash[i];
/* phase 0 always points to the "real" Agg in the hash case */
phasedata->aggnode = node;
phasedata->aggstrategy = node->aggstrategy;
/* but the actual Agg node representing this hash is saved here */
perhash->aggnode = aggnode;
phasedata->gset_lengths[i] = perhash->numCols = aggnode->numCols;
for (j = 0; j < aggnode->numCols; ++j)
cols = bms_add_member(cols, aggnode->grpColIdx[j]);
phasedata->grouped_cols[i] = cols;
phasedata->gset_id[i] = numgsets++;
if (i >= 1)
{
if (bms_equal(phasedata->grouped_cols[i], phasedata->grouped_cols[i - 1]))
phasedata->group_id[i] = phasedata->group_id[i - 1] + 1;
}
all_grouped_cols = bms_add_members(all_grouped_cols, cols);
continue;
}
else
{
AggStatePerPhase phasedata = &aggstate->phases[++phase];
int num_sets;
phasedata->numsets = num_sets = list_length(aggnode->groupingSets);
if (num_sets)
{
phasedata->gset_lengths = palloc(num_sets * sizeof(int));
phasedata->grouped_cols = palloc(num_sets * sizeof(Bitmapset *));
phasedata->gset_id = palloc(num_sets * sizeof(int));
phasedata->group_id = palloc0(num_sets * sizeof(int));
i = 0;
foreach(l, aggnode->groupingSets)
{
int current_length = list_length(lfirst(l));
Bitmapset *cols = NULL;
/* planner forces this to be correct */
for (j = 0; j < current_length; ++j)
cols = bms_add_member(cols, aggnode->grpColIdx[j]);
phasedata->grouped_cols[i] = cols;
phasedata->gset_id[i] = numgsets++;
phasedata->gset_lengths[i] = current_length;
if (i > 0)
{
if (bms_equal(phasedata->grouped_cols[i], phasedata->grouped_cols[i - 1]))
phasedata->group_id[i] = phasedata->group_id[i - 1] + 1;
}
++i;
}
all_grouped_cols = bms_add_members(all_grouped_cols,
phasedata->grouped_cols[0]);
}
else
{
Assert(phaseidx == 0);
phasedata->gset_lengths = NULL;
phasedata->grouped_cols = NULL;
phasedata->group_id = NULL;
phasedata->gset_id = NULL;
}
/*
* If we are grouping, precompute fmgr lookup data for inner loop.
*/
if (aggnode->aggstrategy == AGG_SORTED)
{
int i = 0;
Assert(aggnode->numCols > 0);
/*
* Build a separate function for each subset of columns that
* need to be compared.
*/
phasedata->eqfunctions =
(ExprState **) palloc0(aggnode->numCols * sizeof(ExprState *));
/* for each grouping set */
for (i = 0; i < phasedata->numsets; i++)
{
int length = phasedata->gset_lengths[i];
if (phasedata->eqfunctions[length - 1] != NULL)
continue;
phasedata->eqfunctions[length - 1] =
execTuplesMatchPrepare(scanDesc,
length,
aggnode->grpColIdx,
aggnode->grpOperators,
aggnode->grpCollations,
(PlanState *) aggstate);
}
/* and for all grouped columns, unless already computed */
if (phasedata->eqfunctions[aggnode->numCols - 1] == NULL)
{
phasedata->eqfunctions[aggnode->numCols - 1] =
execTuplesMatchPrepare(scanDesc,
aggnode->numCols,
aggnode->grpColIdx,
aggnode->grpOperators,
aggnode->grpCollations,
(PlanState *) aggstate);
}
}
phasedata->aggnode = aggnode;
phasedata->aggstrategy = aggnode->aggstrategy;
phasedata->sortnode = sortnode;
}
}
/*
* Convert all_grouped_cols to a descending-order list.
*/
i = -1;
while ((i = bms_next_member(all_grouped_cols, i)) >= 0)
aggstate->all_grouped_cols = lcons_int(i, aggstate->all_grouped_cols);
/*
* Set up aggregate-result storage in the output expr context, and also
* allocate my private per-agg working storage
*/
econtext = aggstate->ss.ps.ps_ExprContext;
econtext->ecxt_aggvalues = (Datum *) palloc0(sizeof(Datum) * numaggs);
econtext->ecxt_aggnulls = (bool *) palloc0(sizeof(bool) * numaggs);
peraggs = (AggStatePerAgg) palloc0(sizeof(AggStatePerAggData) * numaggs);
pertransstates = (AggStatePerTrans) palloc0(sizeof(AggStatePerTransData) * numaggs);
aggstate->peragg = peraggs;
aggstate->pertrans = pertransstates;
aggstate->all_pergroups =
(AggStatePerGroup *) palloc0(sizeof(AggStatePerGroup)
* (numGroupingSets + numHashes));
pergroups = aggstate->all_pergroups;
if (node->aggstrategy != AGG_HASHED)
{
for (i = 0; i < numGroupingSets; i++)
{
pergroups[i] = (AggStatePerGroup) palloc0(sizeof(AggStatePerGroupData)
* numaggs);
}
aggstate->pergroups = pergroups;
pergroups += numGroupingSets;
}
/*
* Hashing can only appear in the initial phase.
*/
if (use_hashing)
{
Plan *outerplan = outerPlan(node);
uint64 totalGroups = 0;
int i;
aggstate->hash_metacxt = AllocSetContextCreate(
aggstate->ss.ps.state->es_query_cxt,
"HashAgg meta context",
ALLOCSET_DEFAULT_SIZES);
aggstate->hash_spill_slot = ExecInitExtraTupleSlot(
estate, scanDesc, &TTSOpsMinimalTuple);
/* this is an array of pointers, not structures */
aggstate->hash_pergroup = pergroups;
aggstate->hashentrysize = hash_agg_entry_size(
aggstate->numtrans, outerplan->plan_width, 0);
/*
* Consider all of the grouping sets together when setting the limits
* and estimating the number of partitions. This can be inaccurate
* when there is more than one grouping set, but should still be
* reasonable.
*/
for (i = 0; i < aggstate->num_hashes; i++)
totalGroups += aggstate->perhash[i].aggnode->numGroups;
hash_agg_set_limits(aggstate, aggstate->hashentrysize, totalGroups, 0,
&aggstate->hash_mem_limit,
&aggstate->hash_ngroups_limit,
&aggstate->hash_planned_partitions);
find_hash_columns(aggstate);
build_hash_tables(aggstate);
aggstate->table_filled = false;
}
/*
* Initialize current phase-dependent values to initial phase. The initial
* phase is 1 (first sort pass) for all strategies that use sorting (if
* hashing is being done too, then phase 0 is processed last); but if only
* hashing is being done, then phase 0 is all there is.
*/
if (node->aggstrategy == AGG_HASHED)
{
aggstate->current_phase = 0;
initialize_phase(aggstate, 0);
select_current_set(aggstate, 0, true);
}
else
{
aggstate->current_phase = 1;
initialize_phase(aggstate, 1);
select_current_set(aggstate, 0, false);
}
/* -----------------
* Perform lookups of aggregate function info, and initialize the
* unchanging fields of the per-agg and per-trans data.
*
* We try to optimize by detecting duplicate aggregate functions so that
* their state and final values are re-used, rather than needlessly being
* re-calculated independently. We also detect aggregates that are not
* the same, but which can share the same transition state.
*
* Scenarios:
*
* 1. Identical aggregate function calls appear in the query:
*
* SELECT SUM(x) FROM ... HAVING SUM(x) > 0
*
* Since these aggregates are identical, we only need to calculate
* the value once. Both aggregates will share the same 'aggno' value.
*
* 2. Two different aggregate functions appear in the query, but the
* aggregates have the same arguments, transition functions and
* initial values (and, presumably, different final functions):
*
* SELECT AVG(x), STDDEV(x) FROM ...
*
* In this case we must create a new peragg for the varying aggregate,
* and we need to call the final functions separately, but we need
* only run the transition function once. (This requires that the
* final functions be nondestructive of the transition state, but
* that's required anyway for other reasons.)
*
* For either of these optimizations to be valid, all aggregate properties
* used in the transition phase must be the same, including any modifiers
* such as ORDER BY, DISTINCT and FILTER, and the arguments mustn't
* contain any volatile functions.
* -----------------
*/
aggno = -1;
transno = -1;
foreach(l, aggstate->aggs)
{
AggrefExprState *aggrefstate = (AggrefExprState *) lfirst(l);
Aggref *aggref = aggrefstate->aggref;
AggStatePerAgg peragg;
AggStatePerTrans pertrans;
int existing_aggno;
int existing_transno;
List *same_input_transnos;
Oid inputTypes[FUNC_MAX_ARGS];
int numArguments;
int numDirectArgs;
HeapTuple aggTuple;
Form_pg_aggregate aggform;
AclResult aclresult;
Oid transfn_oid,
finalfn_oid;
bool shareable;
Oid serialfn_oid,
deserialfn_oid;
Expr *finalfnexpr;
Oid aggtranstype;
Datum textInitVal;
Datum initValue;
bool initValueIsNull;
/* Planner should have assigned aggregate to correct level */
Assert(aggref->agglevelsup == 0);
/* 1. Check for already processed aggs which can be re-used */
existing_aggno = find_compatible_peragg(aggref, aggstate, aggno,
&same_input_transnos);
if (existing_aggno != -1)
{
/*
* Existing compatible agg found. so just point the Aggref to the
* same per-agg struct.
*/
aggrefstate->aggno = existing_aggno;
continue;
}
/* Mark Aggref state node with assigned index in the result array */
peragg = &peraggs[++aggno];
peragg->aggref = aggref;
aggrefstate->aggno = aggno;
/* Fetch the pg_aggregate row */
aggTuple = SearchSysCache1(AGGFNOID,
ObjectIdGetDatum(aggref->aggfnoid));
if (!HeapTupleIsValid(aggTuple))
elog(ERROR, "cache lookup failed for aggregate %u",
aggref->aggfnoid);
aggform = (Form_pg_aggregate) GETSTRUCT(aggTuple);
/* Check permission to call aggregate function */
aclresult = pg_proc_aclcheck(aggref->aggfnoid, GetUserId(),
ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_AGGREGATE,
get_func_name(aggref->aggfnoid));
InvokeFunctionExecuteHook(aggref->aggfnoid);
/* planner recorded transition state type in the Aggref itself */
aggtranstype = aggref->aggtranstype;
Assert(OidIsValid(aggtranstype));
/*
* If this aggregation is performing state combines, then instead of
* using the transition function, we'll use the combine function
*/
if (DO_AGGSPLIT_COMBINE(aggref->aggsplit))
{
transfn_oid = aggform->aggcombinefn;
/* If not set then the planner messed up */
if (!OidIsValid(transfn_oid))
elog(ERROR, "combinefn not set for aggregate function");
}
else
transfn_oid = aggform->aggtransfn;
/* Final function only required if we're finalizing the aggregates */
if (DO_AGGSPLIT_SKIPFINAL(aggref->aggsplit))
peragg->finalfn_oid = finalfn_oid = InvalidOid;
else
peragg->finalfn_oid = finalfn_oid = aggform->aggfinalfn;
/*
* If finalfn is marked read-write, we can't share transition states;
* but it is okay to share states for AGGMODIFY_SHAREABLE aggs. Also,
* if we're not executing the finalfn here, we can share regardless.
*/
shareable = (aggform->aggfinalmodify != AGGMODIFY_READ_WRITE) ||
(finalfn_oid == InvalidOid);
peragg->shareable = shareable;
serialfn_oid = InvalidOid;
deserialfn_oid = InvalidOid;
/*
* Check if serialization/deserialization is required. We only do it
* for aggregates that have transtype INTERNAL.
*/
if (aggtranstype == INTERNALOID)
{
/*
* The planner should only have generated a serialize agg node if
* every aggregate with an INTERNAL state has a serialization
* function. Verify that.
*/
if (DO_AGGSPLIT_SERIALIZE(aggref->aggsplit))
{
/* serialization only valid when not running finalfn */
Assert(DO_AGGSPLIT_SKIPFINAL(aggref->aggsplit));
if (!OidIsValid(aggform->aggserialfn))
elog(ERROR, "serialfunc not provided for serialization aggregation");
serialfn_oid = aggform->aggserialfn;
}
/* Likewise for deserialization functions */
if (DO_AGGSPLIT_DESERIALIZE(aggref->aggsplit))
{
/* deserialization only valid when combining states */
Assert(DO_AGGSPLIT_COMBINE(aggref->aggsplit));
if (!OidIsValid(aggform->aggdeserialfn))
elog(ERROR, "deserialfunc not provided for deserialization aggregation");
deserialfn_oid = aggform->aggdeserialfn;
}
}
/* Check that aggregate owner has permission to call component fns */
{
HeapTuple procTuple;
Oid aggOwner;
procTuple = SearchSysCache1(PROCOID,
ObjectIdGetDatum(aggref->aggfnoid));
if (!HeapTupleIsValid(procTuple))
elog(ERROR, "cache lookup failed for function %u",
aggref->aggfnoid);
aggOwner = ((Form_pg_proc) GETSTRUCT(procTuple))->proowner;
ReleaseSysCache(procTuple);
aclresult = pg_proc_aclcheck(transfn_oid, aggOwner,
ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_FUNCTION,
get_func_name(transfn_oid));
InvokeFunctionExecuteHook(transfn_oid);
if (OidIsValid(finalfn_oid))
{
aclresult = pg_proc_aclcheck(finalfn_oid, aggOwner,
ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_FUNCTION,
get_func_name(finalfn_oid));
InvokeFunctionExecuteHook(finalfn_oid);
}
if (OidIsValid(serialfn_oid))
{
aclresult = pg_proc_aclcheck(serialfn_oid, aggOwner,
ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_FUNCTION,
get_func_name(serialfn_oid));
InvokeFunctionExecuteHook(serialfn_oid);
}
if (OidIsValid(deserialfn_oid))
{
aclresult = pg_proc_aclcheck(deserialfn_oid, aggOwner,
ACL_EXECUTE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_FUNCTION,
get_func_name(deserialfn_oid));
InvokeFunctionExecuteHook(deserialfn_oid);
}
}
/*
* Get actual datatypes of the (nominal) aggregate inputs. These
* could be different from the agg's declared input types, when the
* agg accepts ANY or a polymorphic type.
*/
numArguments = get_aggregate_argtypes(aggref, inputTypes);
/* Count the "direct" arguments, if any */
numDirectArgs = list_length(aggref->aggdirectargs);
/* Detect how many arguments to pass to the finalfn */
if (aggform->aggfinalextra)
peragg->numFinalArgs = numArguments + 1;
else
peragg->numFinalArgs = numDirectArgs + 1;
/* Initialize any direct-argument expressions */
peragg->aggdirectargs = ExecInitExprList(aggref->aggdirectargs,
(PlanState *) aggstate);
/*
* build expression trees using actual argument & result types for the
* finalfn, if it exists and is required.
*/
if (OidIsValid(finalfn_oid))
{
build_aggregate_finalfn_expr(inputTypes,
peragg->numFinalArgs,
aggtranstype,
aggref->aggtype,
aggref->inputcollid,
finalfn_oid,
&finalfnexpr);
fmgr_info(finalfn_oid, &peragg->finalfn);
fmgr_info_set_expr((Node *) finalfnexpr, &peragg->finalfn);
}
/* get info about the output value's datatype */
get_typlenbyval(aggref->aggtype,
&peragg->resulttypeLen,
&peragg->resulttypeByVal);
/*
* initval is potentially null, so don't try to access it as a struct
* field. Must do it the hard way with SysCacheGetAttr.
*/
textInitVal = SysCacheGetAttr(AGGFNOID, aggTuple,
Anum_pg_aggregate_agginitval,
&initValueIsNull);
if (initValueIsNull)
initValue = (Datum) 0;
else
initValue = GetAggInitVal(textInitVal, aggtranstype);
/*
* 2. Build working state for invoking the transition function, or
* look up previously initialized working state, if we can share it.
*
* find_compatible_peragg() already collected a list of shareable
* per-Trans's with the same inputs. Check if any of them have the
* same transition function and initial value.
*/
existing_transno = find_compatible_pertrans(aggstate, aggref,
shareable,
transfn_oid, aggtranstype,
serialfn_oid, deserialfn_oid,
initValue, initValueIsNull,
same_input_transnos);
if (existing_transno != -1)
{
/*
* Existing compatible trans found, so just point the 'peragg' to
* the same per-trans struct, and mark the trans state as shared.
*/
pertrans = &pertransstates[existing_transno];
pertrans->aggshared = true;
peragg->transno = existing_transno;
}
else
{
pertrans = &pertransstates[++transno];
build_pertrans_for_aggref(pertrans, aggstate, estate,
aggref, transfn_oid, aggtranstype,
serialfn_oid, deserialfn_oid,
initValue, initValueIsNull,
inputTypes, numArguments);
peragg->transno = transno;
}
ReleaseSysCache(aggTuple);
}
/*
* Update aggstate->numaggs to be the number of unique aggregates found.
* Also set numstates to the number of unique transition states found.
*/
aggstate->numaggs = aggno + 1;
aggstate->numtrans = transno + 1;
/*
* Last, check whether any more aggregates got added onto the node while
* we processed the expressions for the aggregate arguments (including not
* only the regular arguments and FILTER expressions handled immediately
* above, but any direct arguments we might've handled earlier). If so,
* we have nested aggregate functions, which is semantically nonsensical,
* so complain. (This should have been caught by the parser, so we don't
* need to work hard on a helpful error message; but we defend against it
* here anyway, just to be sure.)
*/
if (numaggs != list_length(aggstate->aggs))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("aggregate function calls cannot be nested")));
/* MPP */
aggstate->AggExprId_AttrNum = node->agg_expr_id;
/*
* Build expressions doing all the transition work at once. We build a
* different one for each phase, as the number of transition function
* invocation can differ between phases. Note this'll work both for
* transition and combination functions (although there'll only be one
* phase in the latter case).
*/
for (phaseidx = 0; phaseidx < aggstate->numphases; phaseidx++)
{
AggStatePerPhase phase = &aggstate->phases[phaseidx];
bool dohash = false;
bool dosort = false;
/* phase 0 doesn't necessarily exist */
if (!phase->aggnode)
continue;
if (aggstate->aggstrategy == AGG_MIXED && phaseidx == 1)
{
/*
* Phase one, and only phase one, in a mixed agg performs both
* sorting and aggregation.
*/
dohash = true;
dosort = true;
}
else if (aggstate->aggstrategy == AGG_MIXED && phaseidx == 0)
{
/*
* No need to compute a transition function for an AGG_MIXED phase
* 0 - the contents of the hashtables will have been computed
* during phase 1.
*/
continue;
}
else if (phase->aggstrategy == AGG_PLAIN ||
phase->aggstrategy == AGG_SORTED)
{
dohash = false;
dosort = true;
}
else if (phase->aggstrategy == AGG_HASHED)
{
dohash = true;
dosort = false;
}
else
Assert(false);
phase->evaltrans = ExecBuildAggTrans(aggstate, phase, dosort, dohash,
false);
/* cache compiled expression for outer slot without NULL check */
phase->evaltrans_cache[0][0] = phase->evaltrans;
}
return aggstate;
}
/*
* Build the state needed to calculate a state value for an aggregate.
*
* This initializes all the fields in 'pertrans'. 'aggref' is the aggregate
* to initialize the state for. 'aggtransfn', 'aggtranstype', and the rest
* of the arguments could be calculated from 'aggref', but the caller has
* calculated them already, so might as well pass them.
*/
static void
build_pertrans_for_aggref(AggStatePerTrans pertrans,
AggState *aggstate, EState *estate,
Aggref *aggref,
Oid aggtransfn, Oid aggtranstype,
Oid aggserialfn, Oid aggdeserialfn,
Datum initValue, bool initValueIsNull,
Oid *inputTypes, int numArguments)
{
int numGroupingSets = Max(aggstate->maxsets, 1);
Expr *serialfnexpr = NULL;
Expr *deserialfnexpr = NULL;
ListCell *lc;
int numInputs;
int numDirectArgs;
List *sortlist;
int numSortCols;
int numDistinctCols;
int i;
/* Begin filling in the pertrans data */
pertrans->aggref = aggref;
pertrans->aggshared = false;
pertrans->aggCollation = aggref->inputcollid;
pertrans->transfn_oid = aggtransfn;
pertrans->serialfn_oid = aggserialfn;
pertrans->deserialfn_oid = aggdeserialfn;
pertrans->initValue = initValue;
pertrans->initValueIsNull = initValueIsNull;
/* Count the "direct" arguments, if any */
numDirectArgs = list_length(aggref->aggdirectargs);
/* Count the number of aggregated input columns */
pertrans->numInputs = numInputs = list_length(aggref->args);
pertrans->aggtranstype = aggtranstype;
/*
* When combining states, we have no use at all for the aggregate
* function's transfn. Instead we use the combinefn. In this case, the
* transfn and transfn_oid fields of pertrans refer to the combine
* function rather than the transition function.
*/
if (DO_AGGSPLIT_COMBINE(aggstate->aggsplit))
{
Expr *combinefnexpr;
size_t numTransArgs;
/*
* When combining there's only one input, the to-be-combined added
* transition value from below (this node's transition value is
* counted separately).
*/
pertrans->numTransInputs = 1;
/* account for the current transition state */
numTransArgs = pertrans->numTransInputs + 1;
build_aggregate_combinefn_expr(aggtranstype,
aggref->inputcollid,
aggtransfn,
&combinefnexpr);
fmgr_info(aggtransfn, &pertrans->transfn);
fmgr_info_set_expr((Node *) combinefnexpr, &pertrans->transfn);
pertrans->transfn_fcinfo =
(FunctionCallInfo) palloc(SizeForFunctionCallInfo(2));
InitFunctionCallInfoData(*pertrans->transfn_fcinfo,
&pertrans->transfn,
numTransArgs,
pertrans->aggCollation,
(void *) aggstate, NULL);
/*
* Ensure that a combine function to combine INTERNAL states is not
* strict. This should have been checked during CREATE AGGREGATE, but
* the strict property could have been changed since then.
*/
if (pertrans->transfn.fn_strict && aggtranstype == INTERNALOID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("combine function with transition type %s must not be declared STRICT",
format_type_be(aggtranstype))));
}
else
{
Expr *transfnexpr;
size_t numTransArgs;
/* Detect how many arguments to pass to the transfn */
if (AGGKIND_IS_ORDERED_SET(aggref->aggkind))
pertrans->numTransInputs = numInputs;
else
pertrans->numTransInputs = numArguments;
/* account for the current transition state */
numTransArgs = pertrans->numTransInputs + 1;
/*
* Set up infrastructure for calling the transfn. Note that invtrans
* is not needed here.
*/
build_aggregate_transfn_expr(inputTypes,
numArguments,
numDirectArgs,
aggref->aggvariadic,
aggtranstype,
aggref->inputcollid,
aggtransfn,
InvalidOid,
&transfnexpr,
NULL);
fmgr_info(aggtransfn, &pertrans->transfn);
fmgr_info_set_expr((Node *) transfnexpr, &pertrans->transfn);
pertrans->transfn_fcinfo =
(FunctionCallInfo) palloc(SizeForFunctionCallInfo(numTransArgs));
InitFunctionCallInfoData(*pertrans->transfn_fcinfo,
&pertrans->transfn,
numTransArgs,
pertrans->aggCollation,
(void *) aggstate, NULL);
/*
* If the transfn is strict and the initval is NULL, make sure input
* type and transtype are the same (or at least binary-compatible), so
* that it's OK to use the first aggregated input value as the initial
* transValue. This should have been checked at agg definition time,
* but we must check again in case the transfn's strictness property
* has been changed.
*/
if (pertrans->transfn.fn_strict && pertrans->initValueIsNull)
{
if (numArguments <= numDirectArgs ||
!IsBinaryCoercible(inputTypes[numDirectArgs],
aggtranstype))
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate %u needs to have compatible input type and transition type",
aggref->aggfnoid)));
}
}
/* get info about the state value's datatype */
get_typlenbyval(aggtranstype,
&pertrans->transtypeLen,
&pertrans->transtypeByVal);
if (OidIsValid(aggserialfn))
{
build_aggregate_serialfn_expr(aggserialfn,
&serialfnexpr);
fmgr_info(aggserialfn, &pertrans->serialfn);
fmgr_info_set_expr((Node *) serialfnexpr, &pertrans->serialfn);
pertrans->serialfn_fcinfo =
(FunctionCallInfo) palloc(SizeForFunctionCallInfo(1));
InitFunctionCallInfoData(*pertrans->serialfn_fcinfo,
&pertrans->serialfn,
1,
InvalidOid,
(void *) aggstate, NULL);
}
if (OidIsValid(aggdeserialfn))
{
build_aggregate_deserialfn_expr(aggdeserialfn,
&deserialfnexpr);
fmgr_info(aggdeserialfn, &pertrans->deserialfn);
fmgr_info_set_expr((Node *) deserialfnexpr, &pertrans->deserialfn);
pertrans->deserialfn_fcinfo =
(FunctionCallInfo) palloc(SizeForFunctionCallInfo(2));
InitFunctionCallInfoData(*pertrans->deserialfn_fcinfo,
&pertrans->deserialfn,
2,
InvalidOid,
(void *) aggstate, NULL);
}
/*
* If we're doing either DISTINCT or ORDER BY for a plain agg, then we
* have a list of SortGroupClause nodes; fish out the data in them and
* stick them into arrays. We ignore ORDER BY for an ordered-set agg,
* however; the agg's transfn and finalfn are responsible for that.
*
* Note that by construction, if there is a DISTINCT clause then the ORDER
* BY clause is a prefix of it (see transformDistinctClause).
*/
if (AGGKIND_IS_ORDERED_SET(aggref->aggkind))
{
sortlist = NIL;
numSortCols = numDistinctCols = 0;
}
else if (aggref->aggdistinct)
{
sortlist = aggref->aggdistinct;
numSortCols = numDistinctCols = list_length(sortlist);
Assert(numSortCols >= list_length(aggref->aggorder));
}
else
{
sortlist = aggref->aggorder;
numSortCols = list_length(sortlist);
numDistinctCols = 0;
}
pertrans->numSortCols = numSortCols;
pertrans->numDistinctCols = numDistinctCols;
/*
* If we have either sorting or filtering to do, create a tupledesc and
* slot corresponding to the aggregated inputs (including sort
* expressions) of the agg.
*/
if (numSortCols > 0 || aggref->aggfilter)
{
pertrans->sortdesc = ExecTypeFromTL(aggref->args);
pertrans->sortslot =
ExecInitExtraTupleSlot(estate, pertrans->sortdesc,
&TTSOpsMinimalTuple);
}
if (numSortCols > 0)
{
/*
* We don't implement DISTINCT or ORDER BY aggs in the HASHED case
* (yet)
*/
Assert(aggstate->aggstrategy != AGG_HASHED && aggstate->aggstrategy != AGG_MIXED);
/* If we have only one input, we need its len/byval info. */
if (numInputs == 1)
{
get_typlenbyval(inputTypes[numDirectArgs],
&pertrans->inputtypeLen,
&pertrans->inputtypeByVal);
}
else if (numDistinctCols > 0)
{
/* we will need an extra slot to store prior values */
pertrans->uniqslot =
ExecInitExtraTupleSlot(estate, pertrans->sortdesc,
&TTSOpsMinimalTuple);
}
/* Extract the sort information for use later */
pertrans->sortColIdx =
(AttrNumber *) palloc(numSortCols * sizeof(AttrNumber));
pertrans->sortOperators =
(Oid *) palloc(numSortCols * sizeof(Oid));
pertrans->sortCollations =
(Oid *) palloc(numSortCols * sizeof(Oid));
pertrans->sortNullsFirst =
(bool *) palloc(numSortCols * sizeof(bool));
i = 0;
foreach(lc, sortlist)
{
SortGroupClause *sortcl = (SortGroupClause *) lfirst(lc);
TargetEntry *tle = get_sortgroupclause_tle(sortcl, aggref->args);
/* the parser should have made sure of this */
Assert(OidIsValid(sortcl->sortop));
pertrans->sortColIdx[i] = tle->resno;
pertrans->sortOperators[i] = sortcl->sortop;
pertrans->sortCollations[i] = exprCollation((Node *) tle->expr);
pertrans->sortNullsFirst[i] = sortcl->nulls_first;
i++;
}
Assert(i == numSortCols);
}
if (aggref->aggdistinct)
{
Oid *ops;
Assert(numArguments > 0);
Assert(list_length(aggref->aggdistinct) == numDistinctCols);
ops = palloc(numDistinctCols * sizeof(Oid));
i = 0;
foreach(lc, aggref->aggdistinct)
ops[i++] = ((SortGroupClause *) lfirst(lc))->eqop;
/* lookup / build the necessary comparators */
if (numDistinctCols == 1)
fmgr_info(get_opcode(ops[0]), &pertrans->equalfnOne);
else
pertrans->equalfnMulti =
execTuplesMatchPrepare(pertrans->sortdesc,
numDistinctCols,
pertrans->sortColIdx,
ops,
pertrans->sortCollations,
&aggstate->ss.ps);
pfree(ops);
}
pertrans->sortstates = (Tuplesortstate **)
palloc0(sizeof(Tuplesortstate *) * numGroupingSets);
}
static Datum
GetAggInitVal(Datum textInitVal, Oid transtype)
{
Oid typinput,
typioparam;
char *strInitVal;
Datum initVal;
getTypeInputInfo(transtype, &typinput, &typioparam);
strInitVal = TextDatumGetCString(textInitVal);
initVal = OidInputFunctionCall(typinput, strInitVal,
typioparam, -1);
pfree(strInitVal);
return initVal;
}
/*
* find_compatible_peragg - search for a previously initialized per-Agg struct
*
* Searches the previously looked at aggregates to find one which is compatible
* with this one, with the same input parameters. If no compatible aggregate
* can be found, returns -1.
*
* As a side-effect, this also collects a list of existing, shareable per-Trans
* structs with matching inputs. If no identical Aggref is found, the list is
* passed later to find_compatible_pertrans, to see if we can at least reuse
* the state value of another aggregate.
*/
static int
find_compatible_peragg(Aggref *newagg, AggState *aggstate,
int lastaggno, List **same_input_transnos)
{
int aggno;
AggStatePerAgg peraggs;
*same_input_transnos = NIL;
/* we mustn't reuse the aggref if it contains volatile function calls */
if (contain_volatile_functions((Node *) newagg))
return -1;
peraggs = aggstate->peragg;
/*
* Search through the list of already seen aggregates. If we find an
* existing identical aggregate call, then we can re-use that one. While
* searching, we'll also collect a list of Aggrefs with the same input
* parameters. If no matching Aggref is found, the caller can potentially
* still re-use the transition state of one of them. (At this stage we
* just compare the parsetrees; whether different aggregates share the
* same transition function will be checked later.)
*/
for (aggno = 0; aggno <= lastaggno; aggno++)
{
AggStatePerAgg peragg;
Aggref *existingRef;
peragg = &peraggs[aggno];
existingRef = peragg->aggref;
/* all of the following must be the same or it's no match */
if (newagg->inputcollid != existingRef->inputcollid ||
newagg->aggtranstype != existingRef->aggtranstype ||
newagg->aggstar != existingRef->aggstar ||
newagg->aggvariadic != existingRef->aggvariadic ||
newagg->aggkind != existingRef->aggkind ||
!equal(newagg->args, existingRef->args) ||
!equal(newagg->aggorder, existingRef->aggorder) ||
!equal(newagg->aggdistinct, existingRef->aggdistinct) ||
!equal(newagg->aggfilter, existingRef->aggfilter))
continue;
/* if it's the same aggregate function then report exact match */
if (newagg->aggfnoid == existingRef->aggfnoid &&
newagg->aggtype == existingRef->aggtype &&
newagg->aggcollid == existingRef->aggcollid &&
equal(newagg->aggdirectargs, existingRef->aggdirectargs))
{
list_free(*same_input_transnos);
*same_input_transnos = NIL;
return aggno;
}
/*
* Not identical, but it had the same inputs. If the final function
* permits sharing, return its transno to the caller, in case we can
* re-use its per-trans state. (If there's already sharing going on,
* we might report a transno more than once. find_compatible_pertrans
* is cheap enough that it's not worth spending cycles to avoid that.)
*/
if (peragg->shareable)
*same_input_transnos = lappend_int(*same_input_transnos,
peragg->transno);
}
return -1;
}
/*
* find_compatible_pertrans - search for a previously initialized per-Trans
* struct
*
* Searches the list of transnos for a per-Trans struct with the same
* transition function and initial condition. (The inputs have already been
* verified to match.)
*/
static int
find_compatible_pertrans(AggState *aggstate, Aggref *newagg, bool shareable,
Oid aggtransfn, Oid aggtranstype,
Oid aggserialfn, Oid aggdeserialfn,
Datum initValue, bool initValueIsNull,
List *transnos)
{
ListCell *lc;
/* If this aggregate can't share transition states, give up */
if (!shareable)
return -1;
foreach(lc, transnos)
{
int transno = lfirst_int(lc);
AggStatePerTrans pertrans = &aggstate->pertrans[transno];
/*
* if the transfns or transition state types are not the same then the
* state can't be shared.
*/
if (aggtransfn != pertrans->transfn_oid ||
aggtranstype != pertrans->aggtranstype)
continue;
/*
* The serialization and deserialization functions must match, if
* present, as we're unable to share the trans state for aggregates
* which will serialize or deserialize into different formats.
* Remember that these will be InvalidOid if they're not required for
* this agg node.
*/
if (aggserialfn != pertrans->serialfn_oid ||
aggdeserialfn != pertrans->deserialfn_oid)
continue;
/*
* Check that the initial condition matches, too.
*/
if (initValueIsNull && pertrans->initValueIsNull)
return transno;
if (!initValueIsNull && !pertrans->initValueIsNull &&
datumIsEqual(initValue, pertrans->initValue,
pertrans->transtypeByVal, pertrans->transtypeLen))
return transno;
}
return -1;
}
void
ExecEndAgg(AggState *node)
{
PlanState *outerPlan;
ExecEagerFreeAgg(node);
/*
* We don't actually free any ExprContexts here (see comment in
* ExecFreeExprContext), just unlinking the output one from the plan node
* suffices.
*/
ExecFreeExprContext(&node->ss.ps);
/* clean up tuple table */
ExecClearTuple(node->ss.ss_ScanTupleSlot);
outerPlan = outerPlanState(node);
ExecEndNode(outerPlan);
}
/*
* It's quite different from upstream, because Greenplum share some same works
* with ExecEagerFreeAgg() here.
*/
void
ExecReScanAgg(AggState *node)
{
ExprContext *econtext = node->ss.ps.ps_ExprContext;
PlanState *outerPlan = outerPlanState(node);
int transno;
int numGroupingSets = Max(node->maxsets, 1);
int setno;
node->agg_done = false;
if (node->aggstrategy == AGG_HASHED)
{
/*
* In the hashed case, if we haven't yet built the hash table then we
* can just return; nothing done yet, so nothing to undo. If subnode's
* chgParam is not NULL then it will be re-scanned by ExecProcNode,
* else no reason to re-scan it at all.
*/
if (!node->table_filled)
return;
/*
* If we do have the hash table, and it never spilled, and the subplan
* does not have any parameter changes, and none of our own parameter
* changes affect input expressions of the aggregated functions, then
* we can just rescan the existing hash table; no need to build it
* again.
*/
if (ReuseHashTable(node))
{
ResetTupleHashIterator(node->perhash[0].hashtable,
&node->perhash[0].hashiter);
select_current_set(node, 0, true);
return;
}
}
/* Make sure we have closed any open tuplesorts */
for (transno = 0; transno < node->numtrans; transno++)
{
for (setno = 0; setno < numGroupingSets; setno++)
{
AggStatePerTrans pertrans = &node->pertrans[transno];
if (pertrans->sortstates[setno])
{
tuplesort_end(pertrans->sortstates[setno]);
pertrans->sortstates[setno] = NULL;
}
}
}
/*
* We don't need to ReScanExprContext the output tuple context here;
* ExecReScan already did it. But we do need to reset our per-grouping-set
* contexts, which may have transvalues stored in them. (We use rescan
* rather than just reset because transfns may have registered callbacks
* that need to be run now.) For the AGG_HASHED case, see below.
*/
for (setno = 0; setno < numGroupingSets; setno++)
{
ReScanExprContext(node->aggcontexts[setno]);
}
/* Release first tuple of group, if we have made a copy */
if (node->grp_firstTuple != NULL)
{
heap_freetuple(node->grp_firstTuple);
node->grp_firstTuple = NULL;
}
ExecClearTuple(node->ss.ss_ScanTupleSlot);
/* Forget current agg values */
MemSet(econtext->ecxt_aggvalues, 0, sizeof(Datum) * node->numaggs);
MemSet(econtext->ecxt_aggnulls, 0, sizeof(bool) * node->numaggs);
/*
* With AGG_HASHED/MIXED, the hash table is allocated in a sub-context of
* the hashcontext. This used to be an issue, but now, resetting a context
* automatically deletes sub-contexts too.
*/
if (node->aggstrategy == AGG_HASHED || node->aggstrategy == AGG_MIXED)
{
hashagg_reset_spill_state(node);
node->hash_ever_spilled = false;
node->hash_spill_mode = false;
node->hash_ngroups_current = 0;
ReScanExprContext(node->hashcontext);
/* Rebuild an empty hash table */
build_hash_tables(node);
node->table_filled = false;
/* iterator will be reset when the table is filled */
hashagg_recompile_expressions(node, false, false);
}
if (node->aggstrategy != AGG_HASHED)
{
/*
* Reset the per-group state (in particular, mark transvalues null)
*/
for (setno = 0; setno < numGroupingSets; setno++)
{
MemSet(node->pergroups[setno], 0,
sizeof(AggStatePerGroupData) * node->numaggs);
}
/* reset to phase 1 */
initialize_phase(node, 1);
node->input_done = false;
node->projected_set = -1;
}
if (outerPlan->chgParam == NULL)
ExecReScan(outerPlan);
}
/***********************************************************************
* API exposed to aggregate functions
***********************************************************************/
/*
* AggCheckCallContext - test if a SQL function is being called as an aggregate
*
* The transition and/or final functions of an aggregate may want to verify
* that they are being called as aggregates, rather than as plain SQL
* functions. They should use this function to do so. The return value
* is nonzero if being called as an aggregate, or zero if not. (Specific
* nonzero values are AGG_CONTEXT_AGGREGATE or AGG_CONTEXT_WINDOW, but more
* values could conceivably appear in future.)
*
* If aggcontext isn't NULL, the function also stores at *aggcontext the
* identity of the memory context that aggregate transition values are being
* stored in. Note that the same aggregate call site (flinfo) may be called
* interleaved on different transition values in different contexts, so it's
* not kosher to cache aggcontext under fn_extra. It is, however, kosher to
* cache it in the transvalue itself (for internal-type transvalues).
*/
int
AggCheckCallContext(FunctionCallInfo fcinfo, MemoryContext *aggcontext)
{
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
if (aggcontext)
{
AggState *aggstate = ((AggState *) fcinfo->context);
ExprContext *cxt = aggstate->curaggcontext;
*aggcontext = cxt->ecxt_per_tuple_memory;
}
return AGG_CONTEXT_AGGREGATE;
}
if (fcinfo->context && IsA(fcinfo->context, WindowAggState))
{
if (aggcontext)
*aggcontext = ((WindowAggState *) fcinfo->context)->curaggcontext;
return AGG_CONTEXT_WINDOW;
}
/* this is just to prevent "uninitialized variable" warnings */
if (aggcontext)
*aggcontext = NULL;
return 0;
}
/*
* AggGetAggref - allow an aggregate support function to get its Aggref
*
* If the function is being called as an aggregate support function,
* return the Aggref node for the aggregate call. Otherwise, return NULL.
*
* Aggregates sharing the same inputs and transition functions can get
* merged into a single transition calculation. If the transition function
* calls AggGetAggref, it will get some one of the Aggrefs for which it is
* executing. It must therefore not pay attention to the Aggref fields that
* relate to the final function, as those are indeterminate. But if a final
* function calls AggGetAggref, it will get a precise result.
*
* Note that if an aggregate is being used as a window function, this will
* return NULL. We could provide a similar function to return the relevant
* WindowFunc node in such cases, but it's not needed yet.
*/
Aggref *
AggGetAggref(FunctionCallInfo fcinfo)
{
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
AggState *aggstate = (AggState *) fcinfo->context;
AggStatePerAgg curperagg;
AggStatePerTrans curpertrans;
/* check curperagg (valid when in a final function) */
curperagg = aggstate->curperagg;
if (curperagg)
return curperagg->aggref;
/* check curpertrans (valid when in a transition function) */
curpertrans = aggstate->curpertrans;
if (curpertrans)
return curpertrans->aggref;
}
return NULL;
}
/*
* AggGetTempMemoryContext - fetch short-term memory context for aggregates
*
* This is useful in agg final functions; the context returned is one that
* the final function can safely reset as desired. This isn't useful for
* transition functions, since the context returned MAY (we don't promise)
* be the same as the context those are called in.
*
* As above, this is currently not useful for aggs called as window functions.
*/
MemoryContext
AggGetTempMemoryContext(FunctionCallInfo fcinfo)
{
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
AggState *aggstate = (AggState *) fcinfo->context;
return aggstate->tmpcontext->ecxt_per_tuple_memory;
}
return NULL;
}
/*
* AggStateIsShared - find out whether transition state is shared
*
* If the function is being called as an aggregate support function,
* return true if the aggregate's transition state is shared across
* multiple aggregates, false if it is not.
*
* Returns true if not called as an aggregate support function.
* This is intended as a conservative answer, ie "no you'd better not
* scribble on your input". In particular, will return true if the
* aggregate is being used as a window function, which is a scenario
* in which changing the transition state is a bad idea. We might
* want to refine the behavior for the window case in future.
*/
bool
AggStateIsShared(FunctionCallInfo fcinfo)
{
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
AggState *aggstate = (AggState *) fcinfo->context;
AggStatePerAgg curperagg;
AggStatePerTrans curpertrans;
/* check curperagg (valid when in a final function) */
curperagg = aggstate->curperagg;
if (curperagg)
return aggstate->pertrans[curperagg->transno].aggshared;
/* check curpertrans (valid when in a transition function) */
curpertrans = aggstate->curpertrans;
if (curpertrans)
return curpertrans->aggshared;
}
return true;
}
/*
* AggRegisterCallback - register a cleanup callback for an aggregate
*
* This is useful for aggs to register shutdown callbacks, which will ensure
* that non-memory resources are freed. The callback will occur just before
* the associated aggcontext (as returned by AggCheckCallContext) is reset,
* either between groups or as a result of rescanning the query. The callback
* will NOT be called on error paths. The typical use-case is for freeing of
* tuplestores or tuplesorts maintained in aggcontext, or pins held by slots
* created by the agg functions. (The callback will not be called until after
* the result of the finalfn is no longer needed, so it's safe for the finalfn
* to return data that will be freed by the callback.)
*
* As above, this is currently not useful for aggs called as window functions.
*/
void
AggRegisterCallback(FunctionCallInfo fcinfo,
ExprContextCallbackFunction func,
Datum arg)
{
if (fcinfo->context && IsA(fcinfo->context, AggState))
{
AggState *aggstate = (AggState *) fcinfo->context;
ExprContext *cxt = aggstate->curaggcontext;
RegisterExprContextCallback(cxt, func, arg);
return;
}
elog(ERROR, "aggregate function cannot register a callback in this context");
}
/*
* aggregate_dummy - dummy execution routine for aggregate functions
*
* This function is listed as the implementation (prosrc field) of pg_proc
* entries for aggregate functions. Its only purpose is to throw an error
* if someone mistakenly executes such a function in the normal way.
*
* Perhaps someday we could assign real meaning to the prosrc field of
* an aggregate?
*/
Datum
aggregate_dummy(PG_FUNCTION_ARGS)
{
elog(ERROR, "aggregate function %u called as normal function",
fcinfo->flinfo->fn_oid);
return (Datum) 0; /* keep compiler quiet */
}
static void
ExecEagerFreeAgg(AggState *node)
{
int transno;
int numGroupingSets = Max(node->maxsets, 1);
int setno;
/* Make sure we have closed any open tuplesorts */
if (node->sort_in)
{
tuplesort_end(node->sort_in);
node->sort_in = NULL;
}
if (node->sort_out)
{
tuplesort_end(node->sort_out);
node->sort_out = NULL;
}
hashagg_reset_spill_state(node);
if (node->hash_metacxt != NULL)
{
MemoryContextDelete(node->hash_metacxt);
node->hash_metacxt = NULL;
}
for (transno = 0; transno < node->numtrans; transno++)
{
for (setno = 0; setno < numGroupingSets; setno++)
{
AggStatePerTrans pertrans = &node->pertrans[transno];
if (pertrans->sortstates[setno])
{
tuplesort_end(pertrans->sortstates[setno]);
pertrans->sortstates[setno] = NULL;
}
}
}
/* And ensure any agg shutdown callbacks have been called */
for (setno = 0; setno < numGroupingSets; setno++)
ReScanExprContext(node->aggcontexts[setno]);
if (node->hashcontext)
ReScanExprContext(node->hashcontext);
}
void
ExecSquelchAgg(AggState *node)
{
/*
* Sometimes, ExecSquelchAgg() is called, but the node is rescanned anyway.
* If we destroy the hash table here, then we need to rebuild it later.
* ExecReScanAgg() will try to reuse the hash table if params is not changing
* or affect input expressions, it will rescan the existing hash table.
* Therefore, don't destroy the hash table if reusing hashtable during rescan.
*/
if (!ReuseHashTable(node))
{
ExecEagerFreeAgg(node);
}
ExecSquelchNode(outerPlanState(node));
}
bool
ReuseHashTable(AggState *node)
{
PlanState *outerPlan = outerPlanState(node);
Agg *aggnode = (Agg *) node->ss.ps.plan;
return (outerPlan->chgParam == NULL && !node->hash_ever_spilled &&
!bms_overlap(node->ss.ps.chgParam, aggnode->aggParams));
}
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