database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-14 18:42:34 +03:00
Code Activity

Use ResourceOwner to track WaitEventSets.

Browse Source 
A WaitEventSet holds file descriptors or event handles (on Windows).
If FreeWaitEventSet is not called, those fds or handles are leaked.
Use ResourceOwners to track WaitEventSets, to clean those up
automatically on error.

This was a live bug in async Append nodes, if a FDW's
ForeignAsyncRequest function failed. (In back branches, I will apply a
more localized fix for that based on PG_TRY-PG_FINALLY.)

The added test doesn't check for leaking resources, so it passed even
before this commit. But at least it covers the code path.

In the passing, fix misleading comment on what the 'nevents' argument
to WaitEventSetWait means.

Report by Alexander Lakhin, analysis and suggestion for the fix by
Tom Lane. Fixes bug #17828.

Reviewed-by: Alexander Lakhin, Thomas Munro
Discussion: https://www.postgresql.org/message-id/472235.1678387869@sss.pgh.pa.us
This commit is contained in:
Heikki Linnakangas
2023-11-23 13:31:36 +02:00
parent 414e75540f
commit 50c67c2019
9 changed files with 84 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
src/backend/executor/nodeAppend.c
View File

@ -1025,7 +1025,8 @@ ExecAppendAsyncEventWait(AppendState *node)
/* We should never be called when there are no valid async subplans. */
Assert(node->as_nasyncremain > 0);
node->as_eventset = CreateWaitEventSet(CurrentMemoryContext, nevents);
Assert(node->as_eventset == NULL);
node->as_eventset = CreateWaitEventSet(CurrentResourceOwner, nevents);
AddWaitEventToSet(node->as_eventset, WL_EXIT_ON_PM_DEATH, PGINVALID_SOCKET,
NULL, NULL);
@ -1050,7 +1051,7 @@ ExecAppendAsyncEventWait(AppendState *node)
return;
}
/* We wait on at most EVENT_BUFFER_SIZE events. */
/* Return at most EVENT_BUFFER_SIZE events in one call. */
if (nevents > EVENT_BUFFER_SIZE)
nevents = EVENT_BUFFER_SIZE;