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| author | Bruce Momjian <bruce@momjian.us> | 2025-05-03 12:57:18 -0400 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2025-05-03 12:57:18 -0400 |
| commit | 24987c6f0687576da97b593c6dd5740ccdd23277 (patch) | |
| tree | f949c64ea5d77bd6721f7204862cee56edb20756 /doc | |
| parent | 04b269da56db966bd439bf4634a0f33c166eae2e (diff) | |
| download | postgresql-24987c6f0687576da97b593c6dd5740ccdd23277.tar.gz postgresql-24987c6f0687576da97b593c6dd5740ccdd23277.zip | |
doc PG 18 relnotes: add GROUP BY column elimination item
With a nod to PG 9.6.
Reported-by: jian he
Discussion: https://postgr.es/m/CACJufxEqs=EXZETwtaOooTFhZrtxvSWg8M2uPfzjNtS3wQ6Dzw@mail.gmail.com
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/src/sgml/release-18.sgml | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/doc/src/sgml/release-18.sgml b/doc/src/sgml/release-18.sgml index 66cdeb67961..33e9199d758 100644 --- a/doc/src/sgml/release-18.sgml +++ b/doc/src/sgml/release-18.sgml @@ -285,6 +285,23 @@ This optimization can be disabled using enable_distinct_reordering. </listitem> <!-- +Author: David Rowley <drowley@postgresql.org> +2024-12-12 [bd10ec529] Detect redundant GROUP BY columns using UNIQUE indexes +--> + +<listitem> +<para> +Ignore GROUP BY columns that are functionally dependent on other columns (Zhang Mingli, Jian He, David Rowley) +<ulink url="&commit_baseurl;bd10ec529">§</ulink> +</para> + +<para> +If a GROUP BY clause includes all columns of a unique index, as well as other columns of the same table, those other columns are redundant and can be dropped +from the grouping. This was already true for non-deferred primary keys. +</para> +</listitem> + +<!-- Author: Richard Guo <rguo@postgresql.org> 2024-10-09 [67a54b9e8] Allow pushdown of HAVING clauses with grouping sets --> |