Files
postgresql/src/test
Tom Lane 9f954177b1 Correctly identify which EC members are computable at a plan node.
find_computable_ec_member() had the wrong mental model of what
its primary caller prepare_sort_from_pathkeys() would do with
the selected EquivalenceClass member expression.  We will not
compute the EC expression in a plan node atop the one returning
the passed-in targetlist; rather, the EC expression will be
computed as an additional column of that targetlist.  So any
Var or quasi-Var used in the given tlist is also available to the
EC expression.  In simple cases this makes no difference because
the given tlist is just a list of Vars or quasi-Vars --- but if
we are considering an appendrel member produced by flattening
a UNION ALL, the tlist may contain expressions, resulting in
failure to match and a "could not find pathkey item to sort"
error.

To fix, we can flatten both the tlist and the EC members with
pull_var_clause(), and then just check for subset-ness, so
that the code is actually shorter than before.

While this bug is quite old, the present patch only works back to
v13.  We could possibly make it work in v12 by back-patching parts
of 375398244.  On the whole though I don't like the risk/reward
ratio of that idea.  v12's final release is next month, meaning
there would be no chance to correct matters if the patch causes a
regression.  Since this failure has escaped notice for 14 years,
it's likely nobody will hit it in the field with v12.

Per bug #18652 from Alexander Lakhin.

Andrei Lepikhov and Tom Lane

Discussion: https://postgr.es/m/18652-deaa782ebcca85d1@postgresql.org
2024-10-12 14:56:08 -04:00
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PostgreSQL tests
================

This directory contains a variety of test infrastructure as well as some of the
tests in PostgreSQL. Not all tests are here -- in particular, there are more in
individual contrib/ modules and in src/bin.

Not all these tests get run by "make check". Check src/test/Makefile to see
which tests get run automatically.

authentication/
  Tests for authentication (but see also below)

examples/
  Demonstration programs for libpq that double as regression tests via
  "make check"

isolation/
  Tests for concurrent behavior at the SQL level

kerberos/
  Tests for Kerberos/GSSAPI authentication and encryption

ldap/
  Tests for LDAP-based authentication

locale/
  Sanity checks for locale data, encodings, etc

mb/
  Tests for multibyte encoding (UTF-8) support

modules/
  Extensions used only or mainly for test purposes, generally not suitable
  for installing in production databases

perl/
  Infrastructure for Perl-based TAP tests

recovery/
  Test suite for recovery and replication

regress/
  PostgreSQL's main regression test suite, pg_regress

ssl/
  Tests to exercise and verify SSL certificate handling

subscription/
  Tests for logical replication