From 3452dc5240da43e833118484e1e9b4894d04431c Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Tue, 29 Aug 2017 13:12:23 -0400 Subject: Push tuple limits through Gather and Gather Merge. If we only need, say, 10 tuples in total, then we certainly don't need more than 10 tuples from any single process. Pushing down the limit lets workers exit early when possible. For Gather Merge, there is an additional benefit: a Sort immediately below the Gather Merge can be done as a bounded sort if there is an applicable limit. Robert Haas and Tom Lane Discussion: http://postgr.es/m/CA+TgmoYa3QKKrLj5rX7UvGqhH73G1Li4B-EKxrmASaca2tFu9Q@mail.gmail.com --- src/include/executor/execParallel.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/include/executor/execParallel.h') diff --git a/src/include/executor/execParallel.h b/src/include/executor/execParallel.h index bd0a87fa041..79b886706f7 100644 --- a/src/include/executor/execParallel.h +++ b/src/include/executor/execParallel.h @@ -33,7 +33,7 @@ typedef struct ParallelExecutorInfo } ParallelExecutorInfo; extern ParallelExecutorInfo *ExecInitParallelPlan(PlanState *planstate, - EState *estate, int nworkers); + EState *estate, int nworkers, int64 tuples_needed); extern void ExecParallelFinish(ParallelExecutorInfo *pei); extern void ExecParallelCleanup(ParallelExecutorInfo *pei); extern void ExecParallelReinitialize(ParallelExecutorInfo *pei); -- cgit v1.2.3