Summary:
Ref T6615. Mixing ASC and DESC ordering on a multipart key makes it dramatically less effective (or perhaps totally ineffective).
Reverse the meaning of the `priority` column so it goes in the same direction as the `id` column (both ascending, lower values execute sooner).
Test Plan:
- Queued 1.2M tasks with `bin/worker flood`.
- Processed ~1 task/second with `bin/phd debug taskmaster` before patch.
- Applied patch, took ~5 seconds for ~1.2M rows.
- Processed ~100-200 tasks/second with `bin/phd debug taskmaster` after patch.
- "Next in Queue" query on daemon page dropped from 1.5s to <1ms.
Reviewers: btrahan
Reviewed By: btrahan
Subscribers: aklapper, 20after4, epriestley
Maniphest Tasks: T6615
Differential Revision: https://secure.phabricator.com/D10895
