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

Commit04e9678

Browse files
committed
Code review for nodeGatherMerge.c.
Comment the fields of GatherMergeState, and organize them a bit moresensibly. Comment GMReaderTupleBuffer more usefully too. Improveassorted other comments that were obsolete or just not very good English.Get rid of the use of a GMReaderTupleBuffer for the leader process;that was confusing, since only the "done" field was used, and thatin a way redundant with need_to_scan_locally.In gather_merge_init, avoid calling load_tuple_array foralready-known-exhausted workers. I'm not sure if there's a live bug there,but the case is unlikely to be well tested due to timing considerations.Remove some useless code, such as duplicating the tts_isempty test done byTupIsNull.Remove useless initialization of ps.qual, replacing that with an assertionthat we have no qual to check. (If we did, the code would fail to checkit.)Avoid applying heap_copytuple to a null tuple. While that fails to crash,it's confusing and it makes the code less legible not more so IMO.Propagate a couple of these changes into nodeGather.c, as well.Back-patch to v10, partly because of the possibility that thegather_merge_init change is fixing a live bug, but mostly to keepthe branches in sync to ease future bug fixes.
1 parent41b0dd9 commit04e9678

File tree

3 files changed

+138
-114
lines changed

3 files changed

+138
-114
lines changed

‎src/backend/executor/nodeGather.c

Lines changed: 12 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -71,6 +71,8 @@ ExecInitGather(Gather *node, EState *estate, int eflags)
7171
gatherstate->ps.plan= (Plan*)node;
7272
gatherstate->ps.state=estate;
7373
gatherstate->ps.ExecProcNode=ExecGather;
74+
75+
gatherstate->initialized= false;
7476
gatherstate->need_to_scan_locally= !node->single_copy;
7577
gatherstate->tuples_needed=-1;
7678

@@ -82,10 +84,10 @@ ExecInitGather(Gather *node, EState *estate, int eflags)
8284
ExecAssignExprContext(estate,&gatherstate->ps);
8385

8486
/*
85-
* initialize child expressions
87+
* Gather doesn't support checking a qual (it's always more efficient to
88+
* do it in the child node).
8689
*/
87-
gatherstate->ps.qual=
88-
ExecInitQual(node->plan.qual, (PlanState*)gatherstate);
90+
Assert(!node->plan.qual);
8991

9092
/*
9193
* tuple table initialization
@@ -169,15 +171,16 @@ ExecGather(PlanState *pstate)
169171
*/
170172
pcxt=node->pei->pcxt;
171173
LaunchParallelWorkers(pcxt);
174+
/* We save # workers launched for the benefit of EXPLAIN */
172175
node->nworkers_launched=pcxt->nworkers_launched;
176+
node->nreaders=0;
177+
node->nextreader=0;
173178

174179
/* Set up tuple queue readers to read the results. */
175180
if (pcxt->nworkers_launched>0)
176181
{
177-
node->nreaders=0;
178-
node->nextreader=0;
179-
node->reader=
180-
palloc(pcxt->nworkers_launched*sizeof(TupleQueueReader*));
182+
node->reader=palloc(pcxt->nworkers_launched*
183+
sizeof(TupleQueueReader*));
181184

182185
for (i=0;i<pcxt->nworkers_launched;++i)
183186
{
@@ -316,8 +319,8 @@ gather_readnext(GatherState *gatherstate)
316319
tup=TupleQueueReaderNext(reader, true,&readerdone);
317320

318321
/*
319-
* If this reader is done, remove it. If all readers are done, clean
320-
* up remaining worker state.
322+
* If this reader is done, remove it, and collapse the array. If all
323+
*readers are done, cleanup remaining worker state.
321324
*/
322325
if (readerdone)
323326
{

0 commit comments

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