]> granicus.if.org Git - postgresql/commit
Order active window clauses for greater reuse of Sort nodes.
authorAndrew Gierth <rhodiumtoad@postgresql.org>
Fri, 14 Sep 2018 16:35:42 +0000 (17:35 +0100)
committerAndrew Gierth <rhodiumtoad@postgresql.org>
Fri, 14 Sep 2018 16:35:42 +0000 (17:35 +0100)
commit728202b63cdcd7fb73fdba114903ed235eb02f3a
treea0f4f8f04b68fba0a42faea8335b8bc4cec630cd
parent75f9c4ca5a8047d7a9cfbc7d51a610933d04dc7f
Order active window clauses for greater reuse of Sort nodes.

By sorting the active window list lexicographically by the sort clause
list but putting longer clauses before shorter prefixes, we generate
more chances to elide Sort nodes when building the path.

Author: Daniel Gustafsson (with some editorialization by me)
Reviewed-by: Alexander Kuzmenkov, Masahiko Sawada, Tom Lane
Discussion: https://postgr.es/m/124A7F69-84CD-435B-BA0E-2695BE21E5C2%40yesql.se
src/backend/nodes/list.c
src/backend/optimizer/plan/planner.c
src/test/regress/expected/window.out
src/test/regress/sql/window.sql