Implement OR REPLACE option for CREATE AGGREGATE.

Andrew Gierth <rhodiumtoad@postgresql.org>

Commit: 01bde4fa4c24f4eea0a634d8fcad0b376efda6b1
Author: Andrew Gierth <rhodiumtoad@postgresql.org>
Date: 2019-03-19T01:16:50Z
Releases: 12.0
Implement OR REPLACE option for CREATE AGGREGATE.

Aggregates have acquired a dozen or so optional attributes in recent
years for things like parallel query and moving-aggregate mode; the
lack of an OR REPLACE option to add or change these for an existing
agg makes extension upgrades gratuitously hard. Rectify.

Files

Documentation touched