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Restrict Datum sort optimization to byval types only 

91e9e89dc modified nodeSort.c so that it used datum sorts when the
targetlist of the outer node contained only a single column.  That commit
failed to recognise that the Datum returned by tuplesort_getdatum() must
be pfree'd when the type is a byref type.  Ronan Dunklau did originally
propose the patch with that restriction, but that, probably through my own
fault, got lost during further development work.

Due to the timing of this report (PG15 RC1 is almost out the door), let's
just restrict the datum sort optimization to apply for byval types only.
We might want to look harder into making this work for byref types in
PG16.

Reported-by: Önder Kalacı
Diagnosis-by: Tom Lane
Discussion: https://postgr.es/m/CACawEhVxe0ufR26UcqtU7GYGRuubq3p6ZWPGXL4cxy_uexpAAQ@mail.gmail.com
Backpatch-through: 15, where 91e9e89dc was introduced.
This commit is contained in:
David Rowley 2022-09-29 11:43:00 +13:00
parent 2a66b9bfb7
commit 3a5817695a
1 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
src/backend/executor/nodeSort.c
View File

@ -220,6 +220,7 @@ SortState *
ExecInitSort(Sort *node, EState *estate, int eflags)
{
SortState *sortstate;
TupleDesc outerTupDesc;
SO1_printf("ExecInitSort: %s\n",
"initializing sort node");
@ -274,11 +275,13 @@ ExecInitSort(Sort *node, EState *estate, int eflags)
ExecInitResultTupleSlotTL(&sortstate->ss.ps, &TTSOpsMinimalTuple);
sortstate->ss.ps.ps_ProjInfo = NULL;
outerTupDesc = ExecGetResultType(outerPlanState(sortstate));
/*
* We perform a Datum sort when we're sorting just a single column,
* We perform a Datum sort when we're sorting just a single byval column,
* otherwise we perform a tuple sort.
*/
if (ExecGetResultType(outerPlanState(sortstate))->natts == 1)
if (outerTupDesc->natts == 1 && TupleDescAttr(outerTupDesc, 0)->attbyval)
sortstate->datumSort = true;
else
sortstate->datumSort = false;