database/postgres
database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-05-06 19:59:18 +03:00
Code

Ensure gatherstate->nextreader is properly initialized.

Browse Source 
The previously code worked OK as long as a Gather node was never
rescanned, or if it was rescanned, as long as it got at least as
many workers on rescan as it had originally.  But if the number
of workers ever decreased on a rescan, then it could crash.

Andreas Seltenreich
This commit is contained in:
Robert Haas 2016-12-05 15:54:28 -05:00
parent efeb313506
commit 06fa6670fb
1 changed files with 2 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/backend/executor/nodeGather.c
View File

@ -172,6 +172,7 @@ ExecGather(GatherState *node)
if (pcxt->nworkers_launched > 0)
{
node->nreaders = 0;
node->nextreader = 0;
node->reader =
palloc(pcxt->nworkers_launched * sizeof(TupleQueueReader *));
@ -334,6 +335,7 @@ gather_readnext(GatherState *gatherstate)
CHECK_FOR_INTERRUPTS();
/* Attempt to read a tuple, but don't block if none is available. */
Assert(gatherstate->nextreader < gatherstate->nreaders);
reader = gatherstate->reader[gatherstate->nextreader];
tup = TupleQueueReaderNext(reader, true, &readerdone);