diff options
| author | Robert Haas <rhaas@postgresql.org> | 2016-03-04 12:59:10 -0500 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2016-03-04 12:59:10 -0500 |
| commit | df4685fb0cad1c75970b6e8d0aacca4d03545e04 (patch) | |
| tree | 88691c5fd5004e2099bd2d0725fe7143cd7aa2ca /src/backend/executor/nodeGather.c | |
| parent | 546cd0d7664ee0f120ef3b267d4303190bdfdb94 (diff) | |
Minor optimizations based on ParallelContext having nworkers_launched.
Originally, we didn't have nworkers_launched, so code that used parallel
contexts had to be preprared for the possibility that not all of the
workers requested actually got launched. But now we can count on knowing
the number of workers that were successfully launched, which can shave
off a few cycles and simplify some code slightly.
Amit Kapila, reviewed by Haribabu Kommi, per a suggestion from Peter
Geoghegan.
Diffstat (limited to 'src/backend/executor/nodeGather.c')
| -rw-r--r-- | src/backend/executor/nodeGather.c | 18 |
1 files changed, 7 insertions, 11 deletions
diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c index 16c981b48b2..3f0ed696327 100644 --- a/src/backend/executor/nodeGather.c +++ b/src/backend/executor/nodeGather.c @@ -153,7 +153,6 @@ ExecGather(GatherState *node) if (gather->num_workers > 0 && IsInParallelMode()) { ParallelContext *pcxt; - bool got_any_worker = false; /* Initialize the workers required to execute Gather node. */ if (!node->pei) @@ -169,29 +168,26 @@ ExecGather(GatherState *node) LaunchParallelWorkers(pcxt); /* Set up tuple queue readers to read the results. */ - if (pcxt->nworkers > 0) + if (pcxt->nworkers_launched > 0) { node->nreaders = 0; node->reader = - palloc(pcxt->nworkers * sizeof(TupleQueueReader *)); + palloc(pcxt->nworkers_launched * sizeof(TupleQueueReader *)); - for (i = 0; i < pcxt->nworkers; ++i) + for (i = 0; i < pcxt->nworkers_launched; ++i) { - if (pcxt->worker[i].bgwhandle == NULL) - continue; - shm_mq_set_handle(node->pei->tqueue[i], pcxt->worker[i].bgwhandle); node->reader[node->nreaders++] = CreateTupleQueueReader(node->pei->tqueue[i], fslot->tts_tupleDescriptor); - got_any_worker = true; } } - - /* No workers? Then never mind. */ - if (!got_any_worker) + else + { + /* No workers? Then never mind. */ ExecShutdownGatherWorkers(node); + } } /* Run plan locally if no workers or not single-copy. */ |