From c909bd87ce09b00c15707c9420a01bfc8facad3f Mon Sep 17 00:00:00 2001 From: David Rowley Date: Thu, 22 Jun 2023 12:50:13 +1200 Subject: [PATCH] Doc: mention that extended stats aren't used for joins Statistics defined by the CREATE STATISTICS command are only used to assist with the selectivity estimations of base relations, never for joins. Here we mention this fact in the notes section of the CREATE STATISTICS command. Discussion: https://postgr.es/m/CAApHDvrMuVgDOrmg_EtFDZ=AOovq6EsJNnHH1ddyZ8EqL4yzMw@mail.gmail.com Backpatch-through: 11 --- doc/src/sgml/ref/create_statistics.sgml | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/doc/src/sgml/ref/create_statistics.sgml b/doc/src/sgml/ref/create_statistics.sgml index b43aaf142f5..9dfd9639596 100644 --- a/doc/src/sgml/ref/create_statistics.sgml +++ b/doc/src/sgml/ref/create_statistics.sgml @@ -127,6 +127,12 @@ CREATE STATISTICS [ IF NOT EXISTS ] statistics_na reading it. Once created, however, the ownership of the statistics object is independent of the underlying table(s). + + + Extended statistics are not currently used by the planner for selectivity + estimations made for table joins. This limitation will likely be removed + in a future version of PostgreSQL. +