pg_dump sorts objects by their logical names, e.g. (nspname, relname,
tgname), before dependency-driven reordering. That removes one source
of logically-identical databases differing in their schema-only dumps.
In other words, it helps with schema diffing. The logical name sort
ignored essential sort keys for constraints, operators, PUBLICATION
... FOR TABLE, PUBLICATION ... FOR TABLES IN SCHEMA, operator classes,
and operator families. pg_dump's sort then depended on object OID,
yielding spurious schema diffs. After this change, OIDs affect dump
order only in the event of catalog corruption. While pg_dump also
wrongly ignored pg_collation.collencoding, CREATE COLLATION restrictions
have been keeping that imperceptible in practical use.
Use techniques like we use for object types already having full sort key
coverage. Where the pertinent queries weren't fetching the ignored sort
keys, this adds columns to those queries and stores those keys in memory
for the long term.
The ignorance of sort keys became more problematic when commit
172259afb5 added a schema diff test
sensitive to it. Buildfarm member hippopotamus witnessed that.
However, dump order stability isn't a new goal, and this might avoid
other dump comparison failures. Hence, back-patch to v13 (all supported
versions).
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20250707192654.9e.nmisch@google.com
Backpatch-through: 13
This directory contains the source code distribution of the PostgreSQL
database management system.
PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
Noah Misch
1ca1889ea6