diff options
| author | Bruce Momjian <bruce@momjian.us> | 2020-08-03 17:01:42 -0400 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2020-08-03 17:01:42 -0400 |
| commit | e7a6cd5dcf24c6d4b04d036a4837c7af154c4b49 (patch) | |
| tree | 984fe95764954201713793cf13c8eb3bb0e6aeaa | |
| parent | 72ca61101ad4076941f175b50cc86e6372023034 (diff) | |
| download | postgresql-e7a6cd5dcf24c6d4b04d036a4837c7af154c4b49.tar.gz postgresql-e7a6cd5dcf24c6d4b04d036a4837c7af154c4b49.zip | |
doc: PG 13 relnotes: hash_mem_multiplier can restore old behav.
Document that hash_mem_multiplier can get query behavior closer to the
pre-PG 13 behavior of allowing hashing to use more memory.
Reported-by: Peter Geoghegan
Discussion: https://postgr.es/m/CAH2-Wzn3kwQm_pe6g2=ki+P7+ZRqH5GvFGn6SWfv_j7UUgcLdQ@mail.gmail.com
Backpatch-through: 13 only
| -rw-r--r-- | doc/src/sgml/release-13.sgml | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/doc/src/sgml/release-13.sgml b/doc/src/sgml/release-13.sgml index 18e6497a7f2..0b1051ba824 100644 --- a/doc/src/sgml/release-13.sgml +++ b/doc/src/sgml/release-13.sgml @@ -649,7 +649,10 @@ Author: Jeff Davis <jdavis@postgresql.org> <para> Previously, hash aggregation was avoided if it was expected to use - more than <xref linkend="guc-work-mem"/> memory. + more than <xref linkend="guc-work-mem"/> memory. To reduce the + likelihood of using disk storage for hash aggregation and attain + behavior similar to previous Postgres releases, increase <xref + linkend="guc-hash-mem-multiplier"/>. </para> </listitem> |