Thread: pgsql: Relax overly strict assertion

pgsql: Relax overly strict assertion

From
Alvaro Herrera
Date:
Relax overly strict assertion

Ever since its birth, ReorderBufferBuildTupleCidHash() has contained an
assertion that a catalog tuple cannot change Cmax after acquiring one.  But
that's wrong: if a subtransaction executes DDL that affects that catalog
tuple, and later aborts and another DDL affects the same tuple, it will
change Cmax.  Relax the assertion to merely verify that the Cmax remains
valid and monotonically increasing, instead.

Add a test that tickles the relevant code.

Diagnosed by, and initial patch submitted by: Arseny Sher
Co-authored-by: Arseny Sher
Discussion: https://postgr.es/m/874l9p8hyw.fsf@ars-thinkpad

Branch
------
REL_11_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/c2e0954be36390f06e1a8821921648bc258c38bf

Modified Files
--------------
contrib/test_decoding/expected/ddl.out          | 18 ++++++++++++++++++
contrib/test_decoding/sql/ddl.sql               | 13 +++++++++++++
src/backend/replication/logical/reorderbuffer.c | 14 +++++++++-----
3 files changed, 40 insertions(+), 5 deletions(-)