database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-28 23:42:10 +03:00
Code Activity

Remove memory leak protection from Gather and Gather Merge nodes.

Browse Source 
Before commit 6b65a7fe62, tqueue.c could
perform tuple remapping and thus leak memory, which is why commit
af33039317 made TupleQueueReaderNext
run in a short-lived context.  Now, however, tqueue.c has been reduced
to a shadow of its former self, and there shouldn't be any chance of
leaks any more.  Accordingly, remove some tuple copying and memory
context manipulation to speed up processing.

Patch by me, reviewed by Amit Kapila.  Some testing by Rafia Sabih.

Discussion: http://postgr.es/m/CAA4eK1LSDydwrNjmYSNkfJ3ZivGSWH9SVswh6QpNzsMdj_oOQA@mail.gmail.com
This commit is contained in:
Robert Haas
2017-12-04 10:33:09 -05:00
parent a852cfe967
commit 9f4992e2a9
3 changed files with 5 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
src/backend/executor/nodeGather.c
View File

@ -131,7 +131,6 @@ static TupleTableSlot *
ExecGather(PlanState *pstate)
{
GatherState *node = castNode(GatherState, pstate);
TupleTableSlot *fslot = node->funnel_slot;
TupleTableSlot *slot;
ExprContext *econtext;
@ -205,11 +204,8 @@ ExecGather(PlanState *pstate)
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle. This will also clear
* any previous tuple returned by a TupleQueueReader; to make sure we
* don't leave a dangling pointer around, clear the working slot first.
* storage allocated in the previous tuple cycle.
*/
ExecClearTuple(fslot);
econtext = node->ps.ps_ExprContext;
ResetExprContext(econtext);
@ -258,7 +254,6 @@ gather_getnext(GatherState *gatherstate)
PlanState *outerPlan = outerPlanState(gatherstate);
TupleTableSlot *outerTupleSlot;
TupleTableSlot *fslot = gatherstate->funnel_slot;
MemoryContext tupleContext = gatherstate->ps.ps_ExprContext->ecxt_per_tuple_memory;
HeapTuple tup;
while (gatherstate->nreaders > 0 || gatherstate->need_to_scan_locally)
@ -267,12 +262,7 @@ gather_getnext(GatherState *gatherstate)
if (gatherstate->nreaders > 0)
{
MemoryContext oldContext;
/* Run TupleQueueReaders in per-tuple context */
oldContext = MemoryContextSwitchTo(tupleContext);
tup = gather_readnext(gatherstate);
MemoryContextSwitchTo(oldContext);
if (HeapTupleIsValid(tup))
{
@ -280,7 +270,7 @@ gather_getnext(GatherState *gatherstate)
fslot, /* slot in which to store the tuple */
InvalidBuffer, /* buffer associated with this
* tuple */
false); /* slot should not pfree tuple */
true); /* pfree tuple when done with it */
return fslot;
}
}