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When executing an UPDATE with a RETURNING clause on a table with a BEFORE UPDATE row trigger, the computation of the OLD values in the RETURNING list was incorrect if the target tuple was concurrently updated by another session, at isolation level READ COMMITTED. The problem was that the trigger code would lock the target tuple, waiting for the other session to commit, and then fetch the updated target tuple, but ExecUpdate() would not realise that the target tuple had changed, and use the outdated target tuple for computing OLD values. Fix by having ExecUpdate() check the TM_FailureData from trigger execution and re-fetch the target tuple if necessary. Re-fetching the target tuple like this is a little inefficient, but probably negligible compared to the trigger execution and update. A better long-term fix might be to move the EPQ code out of trigger.c, and let ExecUpdate() handle it, like ExecMergeMatched() does, but that would likely mean changing the trigger API, which seems a bit much for back-patching. Backpatch to v18, where support for RETURNING OLD/NEW was added. Bug: #19536 Reported-by: Jonas Boberg <bobergj@gmail.com> Diagnosed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Author: Dean Rasheed <dean.a.rasheed@gmail.com> Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com> Discussion: https://postgr.es/m/19536-73ce5847e6c0e7b1@postgresql.org Backpatch-through: 18 |
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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