From 7fc0c4c9ec0151e31e8c23daa40e9871c360181b Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Fri, 2 Nov 2018 09:10:59 -0400 Subject: [PATCH] GUC: adjust effective_cache_size docs and SQL description Clarify that effective_cache_size is both kernel buffers and shared buffers. Reported-by: nat@makarevitch.org Discussion: https://postgr.es/m/153685164808.22334.15432535018443165207@wrigleys.postgresql.org Backpatch-through: 9.3 --- doc/src/sgml/config.sgml | 3 ++- src/backend/utils/misc/guc.c | 7 +++---- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 0e610741408..1026cc80c1c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -2902,7 +2902,8 @@ include 'filename' used. When setting this parameter you should consider both PostgreSQL's shared buffers and the portion of the kernel's disk cache that will be used for - PostgreSQL data files. Also, take + PostgreSQL data files, though some + data might exist in both places. Also, take into account the expected number of concurrent queries on different tables, since they will have to share the available space. This parameter has no effect on the size of shared diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 7f1e7565231..6cbfaabf9e7 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -2406,10 +2406,9 @@ static struct config_int ConfigureNamesInt[] = { {"effective_cache_size", PGC_USERSET, QUERY_TUNING_COST, - gettext_noop("Sets the planner's assumption about the size of the disk cache."), - gettext_noop("That is, the portion of the kernel's disk cache that " - "will be used for PostgreSQL data files. This is measured in disk " - "pages, which are normally 8 kB each."), + gettext_noop("Sets the planner's assumption about the size of the data cache."), + gettext_noop("That is, the size of the cache used for PostgreSQL data files. " + "This is measured in disk pages, which are normally 8 kB each."), GUC_UNIT_BLOCKS, }, &effective_cache_size,