A partition drop that finally ran

A partitioning scheme built in 2023 for a retention policy that nobody had authority to enforce until this year.

ALTER TABLE events DROP PARTITION p2023_08;
-- 1.8 seconds, 41 GB reclaimed

-- and the seventeen that followed, one a day for
-- seventeen days, because dropping seventeen at once
-- is a single ALTER holding a metadata lock for
-- long enough to matter.

Dropping one partition a day rather than all of them at once is the difference between a series of two-second operations and one lock nobody can predict the length of. The two-year gap between building the mechanism and being allowed to use it is the honest part of this — the technical work was three days and the authorisation was eighteen months.