From: Bruce Momjian Date: Fri, 2 Nov 2018 13:11:00 +0000 (-0400) Subject: GUC: adjust effective_cache_size docs and SQL description X-Git-Tag: REL9_6_11~7 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2a279b6255c2a7a1938b85dc5c9d787b59eefee0;p=postgresql 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 --- diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index e6bbe8af98..5189e8e26c 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -3760,7 +3760,8 @@ include_dir 'conf.d' 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 f33160bf69..d0d3903f20 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -2738,10 +2738,9 @@ 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,