From e1947f6c3ed8bda397295f555fa9e3fe39d50143 Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Tue, 30 Jul 2019 19:17:12 +0200 Subject: [PATCH] Don't build extended statistics on inheritance trees When performing ANALYZE on inheritance trees, we collect two samples for each relation - one for the relation alone, and one for the inheritance subtree (relation and its child relations). And then we build statistics on each sample, so for each relation we get two sets of statistics. For regular (per-column) statistics this works fine, because the catalog includes a flag differentiating statistics built from those two samples. But we don't have such flag in the extended statistics catalogs, and we ended up updating the same row twice, triggering this error: ERROR: tuple already updated by self The simplest solution is to disable extended statistics on inheritance trees, which is what this commit is doing. In the future we may need to do something similar to per-column statistics, but that requires adding a flag to the catalog - and that's not backpatchable. Moreover, the current selectivity estimation code only works with individual relations, so building statistics on inheritance trees would be pointless anyway. Author: Tomas Vondra Backpatch-to: 10- Discussion: https://postgr.es/m/20190618231233.GA27470@telsasoft.com Reported-by: Justin Pryzby --- src/backend/commands/analyze.c | 12 +++++++++--- src/test/regress/expected/stats_ext.out | 8 ++++++++ src/test/regress/sql/stats_ext.sql | 8 ++++++++ 3 files changed, 25 insertions(+), 3 deletions(-) diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c index d7004e5313..faabbeb002 100644 --- a/src/backend/commands/analyze.c +++ b/src/backend/commands/analyze.c @@ -573,9 +573,15 @@ do_analyze_rel(Relation onerel, VacuumParams *params, thisdata->attr_cnt, thisdata->vacattrstats); } - /* Build extended statistics (if there are any). */ - BuildRelationExtStatistics(onerel, totalrows, numrows, rows, attr_cnt, - vacattrstats); + /* + * Build extended statistics (if there are any). + * + * For now we only build extended statistics on individual relations, + * not for relations representing inheritance trees. + */ + if (!inh) + BuildRelationExtStatistics(onerel, totalrows, numrows, rows, + attr_cnt, vacattrstats); } /* diff --git a/src/test/regress/expected/stats_ext.out b/src/test/regress/expected/stats_ext.out index 94b8a8f8b8..d782ebcfea 100644 --- a/src/test/regress/expected/stats_ext.out +++ b/src/test/regress/expected/stats_ext.out @@ -103,6 +103,14 @@ ANALYZE ab1 (a); WARNING: statistics object "public.ab1_a_b_stats" could not be computed for relation "public.ab1" ANALYZE ab1; DROP TABLE ab1; +-- Ensure we can build statistics for tables with inheritance. +CREATE TABLE ab1 (a INTEGER, b INTEGER); +CREATE TABLE ab1c () INHERITS (ab1); +INSERT INTO ab1 VALUES (1,1); +CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1; +ANALYZE ab1; +DROP TABLE ab1 CASCADE; +NOTICE: drop cascades to table ab1c -- Verify supported object types for extended statistics CREATE schema tststats; CREATE TABLE tststats.t (a int, b int, c text); diff --git a/src/test/regress/sql/stats_ext.sql b/src/test/regress/sql/stats_ext.sql index 4bc1536727..d506e8238c 100644 --- a/src/test/regress/sql/stats_ext.sql +++ b/src/test/regress/sql/stats_ext.sql @@ -73,6 +73,14 @@ ANALYZE ab1 (a); ANALYZE ab1; DROP TABLE ab1; +-- Ensure we can build statistics for tables with inheritance. +CREATE TABLE ab1 (a INTEGER, b INTEGER); +CREATE TABLE ab1c () INHERITS (ab1); +INSERT INTO ab1 VALUES (1,1); +CREATE STATISTICS ab1_a_b_stats ON a, b FROM ab1; +ANALYZE ab1; +DROP TABLE ab1 CASCADE; + -- Verify supported object types for extended statistics CREATE schema tststats;