From: | Tomas Vondra <tomas(dot)vondra(at)postgresql(dot)org> |
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To: | pgsql-committers(at)lists(dot)postgresql(dot)org |
Subject: | pgsql: Consider unsorted paths in generate_useful_gather_paths |
Date: | 2020-12-21 17:29:03 |
Message-ID: | E1krOzX-000543-RP@gemulon.postgresql.org |
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Lists: | pgsql-committers |
Consider unsorted paths in generate_useful_gather_paths
generate_useful_gather_paths used to skip unsorted paths (without any
pathkeys), but that is unnecessary - the later code actually can handle
such paths just fine by adding a Sort node. This is clearly a thinko,
preventing construction of useful plans.
Backpatch to 13, where Incremental Sort was introduced.
Author: James Coleman
Reviewed-by: Tomas Vondra
Backpatch-through: 13
Discussion: https://postgr.es/m/CAAaqYe8cK3g5CfLC4w7bs=hC0mSksZC=H5M8LSchj5e5OxpTAg@mail.gmail.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/f4a3c0b06250ddc8ae09b59b87cf68e9bc0d7ca1
Modified Files
--------------
src/backend/optimizer/path/allpaths.c | 11 ++---------
src/test/regress/expected/incremental_sort.out | 13 +++++++++++++
src/test/regress/sql/incremental_sort.sql | 4 ++++
3 files changed, 19 insertions(+), 9 deletions(-)
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