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Allow parallel aggregate on string_agg and array_agg

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This adds combine, serial and deserial functions for the array_agg() and
string_agg() aggregate functions, thus allowing these aggregates to
partake in partial aggregations.  This allows both parallel aggregation to
take place when these aggregates are present and also allows additional
partition-wise aggregation plan shapes to include plans that require
additional aggregation once the partially aggregated results from the
partitions have been combined.

Author: David Rowley
Reviewed-by: Andres Freund, Tomas Vondra, Stephen Frost, Tom Lane
Discussion: https://postgr.es/m/CAKJS1f9sx_6GTcvd6TMuZnNtCh0VhBzhX6FZqw17TgVFH-ga_A@mail.gmail.com
This commit is contained in:
David Rowley
2023-01-23 17:35:01 +13:00
parent 5a3a95385b
commit 16fd03e956
13 changed files with 1103 additions and 30 deletions
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37
src/backend/parser/parse_agg.c
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@ -14,6 +14,7 @@
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "catalog/pg_aggregate.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_type.h"
@ -28,7 +29,7 @@
#include "rewrite/rewriteManip.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
typedef struct
{
@ -1947,6 +1948,40 @@ resolve_aggregate_transtype(Oid aggfuncid,
return aggtranstype;
}
/*
* agg_args_support_sendreceive
* Returns true if all non-byval of aggref's arg types have send and
* receive functions.
*/
bool
agg_args_support_sendreceive(Aggref *aggref)
{
ListCell *lc;
foreach(lc, aggref->args)
{
HeapTuple typeTuple;
Form_pg_type pt;
TargetEntry *tle = (TargetEntry *) lfirst(lc);
Oid type = exprType((Node *) tle->expr);
typeTuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(type));
if (!HeapTupleIsValid(typeTuple))
elog(ERROR, "cache lookup failed for type %u", type);
pt = (Form_pg_type) GETSTRUCT(typeTuple);
if (!pt->typbyval &&
(!OidIsValid(pt->typsend) || !OidIsValid(pt->typreceive)))
{
ReleaseSysCache(typeTuple);
return false;
}
ReleaseSysCache(typeTuple);
}
return true;
}
/*
* Create an expression tree for the transition function of an aggregate.
* This is needed so that polymorphic functions can be used within an