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| author | Robert Haas <rhaas@postgresql.org> | 2017-10-27 16:04:01 +0200 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2017-10-27 16:04:10 +0200 |
| commit | 965a16fa9f8c316c30f4ada3c1c98b5dd4666f25 (patch) | |
| tree | e38839a9e424572faf810e0f9bb3b7d2c84320f4 /src/backend/executor | |
| parent | 6a81ba1d4d26b46636d652a3a56143c159da899c (diff) | |
| download | postgresql-965a16fa9f8c316c30f4ada3c1c98b5dd4666f25.tar.gz postgresql-965a16fa9f8c316c30f4ada3c1c98b5dd4666f25.zip | |
Fix mistaken failure to allow parallelism in corner case.
If we try to run a parallel plan in serial mode because, for example,
it's going to be scanned via a cursor, but for some reason we're
already in parallel mode (for example because an outer query is
running in parallel), we'd incorrectly try to launch workers.
Fix by adding a flag to the EState, so that we can be certain that
ExecutePlan() and ExecGather()/ExecGatherMerge() will have the same
idea about whether we are executing serially or in parallel.
Report and fix by Amit Kapila with help from Kuntal Ghosh. A few
tweaks by me.
Discussion: http://postgr.es/m/CAA4eK1+_BuZrmVCeua5Eqnm4Co9DAXdM5HPAOE2J19ePbR912Q@mail.gmail.com
Diffstat (limited to 'src/backend/executor')
| -rw-r--r-- | src/backend/executor/execMain.c | 1 | ||||
| -rw-r--r-- | src/backend/executor/execUtils.c | 2 | ||||
| -rw-r--r-- | src/backend/executor/nodeGather.c | 2 | ||||
| -rw-r--r-- | src/backend/executor/nodeGatherMerge.c | 2 |
4 files changed, 5 insertions, 2 deletions
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c index ac7e0fb48b3..684470928a4 100644 --- a/src/backend/executor/execMain.c +++ b/src/backend/executor/execMain.c @@ -1704,6 +1704,7 @@ ExecutePlan(EState *estate, if (!execute_once || dest->mydest == DestIntoRel) use_parallel_mode = false; + estate->es_use_parallel_mode = use_parallel_mode; if (use_parallel_mode) EnterParallelMode(); diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c index c3988468795..a5925ca7e3b 100644 --- a/src/backend/executor/execUtils.c +++ b/src/backend/executor/execUtils.c @@ -156,6 +156,8 @@ CreateExecutorState(void) estate->es_epqScanDone = NULL; estate->es_sourceText = NULL; + estate->es_use_parallel_mode = false; + /* * Return the executor state structure */ diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c index 3be735f5c33..89f592828c1 100644 --- a/src/backend/executor/nodeGather.c +++ b/src/backend/executor/nodeGather.c @@ -149,7 +149,7 @@ ExecGather(PlanState *pstate) * Sometimes we might have to run without parallelism; but if parallel * mode is active then we can try to fire up some workers. */ - if (gather->num_workers > 0 && IsInParallelMode()) + if (gather->num_workers > 0 && estate->es_use_parallel_mode) { ParallelContext *pcxt; diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c index c0c285bd611..6b173543564 100644 --- a/src/backend/executor/nodeGatherMerge.c +++ b/src/backend/executor/nodeGatherMerge.c @@ -193,7 +193,7 @@ ExecGatherMerge(PlanState *pstate) * Sometimes we might have to run without parallelism; but if parallel * mode is active then we can try to fire up some workers. */ - if (gm->num_workers > 0 && IsInParallelMode()) + if (gm->num_workers > 0 && estate->es_use_parallel_mode) { ParallelContext *pcxt; |