diff options
| author | Peter Geoghegan | 2022-02-17 02:41:52 +0000 |
|---|---|---|
| committer | Peter Geoghegan | 2022-02-17 02:41:52 +0000 |
| commit | 8f388f6f554b113f25a53fe3237238d2c58ed1eb (patch) | |
| tree | 2366a367511bb0dd101bd46a5a08428a215319cd /doc/src | |
| parent | 74388a1ac36d2f0206c5477eeddc636d7947a5a4 (diff) | |
Increase hash_mem_multiplier default to 2.0.
Double the default setting for hash_mem_multiplier, from 1.0 to 2.0.
This setting makes hash-based executor nodes use twice the usual
work_mem limit.
The PostgreSQL 15 release notes should have a compatibility note about
this change.
Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-Wzndc_ROk6CY-bC6p9O53q974Y0Ey4WX8jcPbuTZYM4Q3A@mail.gmail.com
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/config.sgml | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 53b361e7a92..d99bf38e677 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1849,9 +1849,8 @@ include_dir 'conf.d' operations can use. The final limit is determined by multiplying <varname>work_mem</varname> by <varname>hash_mem_multiplier</varname>. The default value is - 1.0, which makes hash-based operations subject to the same - simple <varname>work_mem</varname> maximum as sort-based - operations. + 2.0, which makes hash-based operations use twice the usual + <varname>work_mem</varname> base amount. </para> <para> Consider increasing <varname>hash_mem_multiplier</varname> in @@ -1859,7 +1858,7 @@ include_dir 'conf.d' occurrence, especially when simply increasing <varname>work_mem</varname> results in memory pressure (memory pressure typically takes the form of intermittent out of - memory errors). A setting of 1.5 or 2.0 may be effective with + memory errors). The default setting of 2.0 is often effective with mixed workloads. Higher settings in the range of 2.0 - 8.0 or more may be effective in environments where <varname>work_mem</varname> has already been increased to 40MB |