Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commit468abb8

Browse files
committed
Fix incorrect logic for choosing the next Parallel Append subplan
In499be01 support for pruning unneeded Append subnodes was added.The logic in that commit was not correctly checking if the next subplanwas in fact a valid subplan. This could cause parallel workers processesto be given a subplan to work on which didn't require any work.Per code review following an otherwise unexplained regression failure inbuildfarm member Pademelon. (We haven't been able to reproduce thefailure, so this is a bit of a blind fix in terms of whether it'llactually fix it; but it is a clear bug nonetheless).In passing, also add a comment to explain what first_partial_plan means.Author: David RowleyDiscussion:https://postgr.es/m/CAKJS1f_E5r05hHUVG3UmCQJ49DGKKHtN=SHybD44LdzBn+CJng@mail.gmail.com
1 parentd775482 commit468abb8

File tree

2 files changed

+43
-12
lines changed

2 files changed

+43
-12
lines changed

‎src/backend/executor/nodeAppend.c

Lines changed: 38 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -547,6 +547,11 @@ choose_next_subplan_for_leader(AppendState *node)
547547
LWLockRelease(&pstate->pa_lock);
548548
return false;
549549
}
550+
551+
/*
552+
* We needn't pay attention to as_valid_subplans here as all invalid
553+
* plans have been marked as finished.
554+
*/
550555
node->as_whichplan--;
551556
}
552557

@@ -612,18 +617,28 @@ choose_next_subplan_for_worker(AppendState *node)
612617
/* Save the plan from which we are starting the search. */
613618
node->as_whichplan=pstate->pa_next_plan;
614619

615-
/* Loop until we find a subplan to execute. */
620+
/* Loop until we find avalidsubplan to execute. */
616621
while (pstate->pa_finished[pstate->pa_next_plan])
617622
{
618-
if (pstate->pa_next_plan<node->as_nplans-1)
623+
intnextplan;
624+
625+
nextplan=bms_next_member(node->as_valid_subplans,
626+
pstate->pa_next_plan);
627+
if (nextplan >=0)
619628
{
620-
/* Advance to next plan. */
621-
pstate->pa_next_plan++;
629+
/* Advance tothenext valid plan. */
630+
pstate->pa_next_plan=nextplan;
622631
}
623632
elseif (node->as_whichplan>append->first_partial_plan)
624633
{
625-
/* Loop back to first partial plan. */
626-
pstate->pa_next_plan=append->first_partial_plan;
634+
/*
635+
* Try looping back to the first valid partial plan, if there is
636+
* one. If there isn't, arrange to bail out below.
637+
*/
638+
nextplan=bms_next_member(node->as_valid_subplans,
639+
append->first_partial_plan-1);
640+
pstate->pa_next_plan=
641+
nextplan<0 ?node->as_whichplan :nextplan;
627642
}
628643
else
629644
{
@@ -644,16 +659,27 @@ choose_next_subplan_for_worker(AppendState *node)
644659
}
645660

646661
/* Pick the plan we found, and advance pa_next_plan one more time. */
647-
node->as_whichplan=pstate->pa_next_plan++;
648-
if (pstate->pa_next_plan >=node->as_nplans)
662+
node->as_whichplan=pstate->pa_next_plan;
663+
pstate->pa_next_plan=bms_next_member(node->as_valid_subplans,
664+
pstate->pa_next_plan);
665+
666+
/*
667+
* If there are no more valid plans then try setting the next plan to the
668+
* first valid partial plan.
669+
*/
670+
if (pstate->pa_next_plan<0)
649671
{
650-
if (append->first_partial_plan<node->as_nplans)
651-
pstate->pa_next_plan=append->first_partial_plan;
672+
intnextplan=bms_next_member(node->as_valid_subplans,
673+
append->first_partial_plan-1);
674+
675+
if (nextplan >=0)
676+
pstate->pa_next_plan=nextplan;
652677
else
653678
{
654679
/*
655-
* We have only non-partial plans, and we already chose the last
656-
* one; so arrange for the other workers to immediately bail out.
680+
* There are no valid partial plans, and we already chose the last
681+
* non-partial plan; so flag that there's nothing more for our
682+
* fellow workers to do.
657683
*/
658684
pstate->pa_next_plan=INVALID_SUBPLAN_INDEX;
659685
}

‎src/include/nodes/plannodes.h

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -255,6 +255,11 @@ typedef struct Append
255255
/* RT indexes of non-leaf tables in a partition tree */
256256
List*partitioned_rels;
257257
List*appendplans;
258+
259+
/*
260+
* All 'appendplans' preceding this index are non-partial plans. All
261+
* 'appendplans' from this index onwards are partial plans.
262+
*/
258263
intfirst_partial_plan;
259264

260265
/*

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp