From 77cd477c4ba885cfa1ba67beaa82e06f2e182b85 Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Tue, 26 Apr 2016 08:31:38 -0400 Subject: Enable parallel query by default. Change max_parallel_degree default from 0 to 2. It is possible that this is not a good idea, or that we should go with 1 worker rather than 2, but we won't find out without trying it. Along the way, reword the documentation for max_parallel_degree a little bit to hopefully make it more clear. Discussion: 20160420174631.3qjjhpwsvvx5bau5@alap3.anarazel.de --- src/backend/optimizer/path/costsize.c | 2 +- src/backend/utils/misc/guc.c | 2 +- src/backend/utils/misc/postgresql.conf.sample | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) (limited to 'src') diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c index 4917922ab57..fcb18732d85 100644 --- a/src/backend/optimizer/path/costsize.c +++ b/src/backend/optimizer/path/costsize.c @@ -113,7 +113,7 @@ int effective_cache_size = DEFAULT_EFFECTIVE_CACHE_SIZE; Cost disable_cost = 1.0e10; -int max_parallel_degree = 0; +int max_parallel_degree = 2; bool enable_seqscan = true; bool enable_indexscan = true; diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 60856dda198..26ca06cfc25 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -2662,7 +2662,7 @@ static struct config_int ConfigureNamesInt[] = NULL }, &max_parallel_degree, - 0, 0, MAX_BACKENDS, + 2, 0, MAX_BACKENDS, NULL, NULL, NULL }, diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 14b537ffb17..f3e3de0568f 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -167,7 +167,7 @@ #effective_io_concurrency = 1 # 1-1000; 0 disables prefetching #max_worker_processes = 8 -#max_parallel_degree = 0 # max number of worker processes per node +#max_parallel_degree = 2 # max number of worker processes per node #old_snapshot_threshold = -1 # 1min-60d; -1 disables; 0 is immediate # (change requires restart) #backend_flush_after = 0 # 0 disables, -- cgit v1.2.3