Summary: Ref T13613. Improve the performance of this migration by using a temporary table and an "UPDATE x JOIN y ..." pattern.
Test Plan:
- Ran on `secure`, got exit after a few seconds since the migration is idempotent and changesets already had PHIDs.
- Ran on `secure` with the `continue;` commented out, got valid new PHIDs in 53s (from 153s).
- Tried a larger page size (16K), didn't see any improvement.
- From "--trace", client PHID generation seems to be the limiting factor.
Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam
Maniphest Tasks: T13613
Differential Revision: https://secure.phabricator.com/D21570
Summary:
Ref T13605. Changesets currently have no PHID, which limits their ability to use standard API infrastructure.
Give them a PHID, since there's no reason they don't have one other than their age.
Test Plan:
- Ran migrations, saw PHIDs populated.
- Created new changesets, saw PHIDs.
Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam
Maniphest Tasks: T13605
Differential Revision: https://secure.phabricator.com/D21557
