From a4a8c0de2b8120b909510ebd33f28c29b038e685 Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Tue, 26 Sep 2023 19:44:21 -0400 Subject: [PATCH] doc: clarify the effect of concurrent work_mem allocations Reported-by: Sami Imseih Discussion: https://postgr.es/m/66590882-F48C-4A25-83E3-73792CF8C51F@amazon.com Backpatch-through: 11 --- doc/src/sgml/config.sgml | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index c6c33d272b..6e35801625 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1582,9 +1582,10 @@ include_dir 'conf.d' Specifies the amount of memory to be used by internal sort operations and hash tables before writing to temporary disk files. The value defaults to four megabytes (4MB). - Note that for a complex query, several sort or hash operations might be - running in parallel; each operation will be allowed to use as much memory - as this value specifies before it starts to write data into temporary + Note that a complex query might perform several sort and hash + operations at the same time, with each operation generally being + allowed to use as much memory as this value specifies before it + starts to write data into temporary files. Also, several running sessions could be doing such operations concurrently. Therefore, the total memory used could be many times the value of work_mem; it is necessary to