System catalogue

Contains system tables and built-in data types, functions, and operators

The system catalogue contains system tables and other built-in objects such as data types, functions, and operators.

Modifying the system catalogue

In principle, the system catalogue is not intended to be user-modifiable.

Beginning with PostgreSQL 12, it is now possible to cleanly run ALTER TABLE on system catalogue tables (commit 590a8702); use-case for this situation is to modify storage parameters (reloptions), e.g. fillfactor or autovacuum settings.

Note this requires the configuration parameter allow_system_table_mods to be set; any modifications should be made with care.


System catalogue

See also

System catalogue tables