Horton

Skip system attributes when applying mvdistinct stats

Tomas Vondra <tomas.vondra@postgresql.org>

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Commit: 25a9ff6cadbb2099a5f53876d9e29f35a080df43
Author: Tomas Vondra <tomas.vondra@postgresql.org>
Date: 2019-11-16T00:58:38Z
Releases: 11.7 
Skip system attributes when applying mvdistinct stats

When estimating number of distinct groups, we failed to ignore system
attributes when matching the group expressions to mvdistinct stats,
causing failures like

  ERROR: negative bitmapset member not allowed

Fix that by simply skipping anything that is not a regular attribute.
Backpatch to PostgreSQL 10, where the extended stats were introduced.

Bug: #16111
Reported-by: Tuomas Leikola
Author: Tomas Vondra
Backpatch-through: 10
Discussion: https://postgr.es/m/16111-687799584c3a7e73@postgresql.org

Files

PathChange+/−
src/backend/utils/adt/selfuncs.c modified +14 −5
src/test/regress/expected/stats_ext.out modified +12 −0
src/test/regress/sql/stats_ext.sql modified +4 −0

Discussion