add build_copr_id index and build_chroot(status, started_on)
This is because of query:
SELECT COUNT(*) as result
FROM build_chroot JOIN build on build.id = build_chroot.build_id
WHERE
build.submitted_on < 1547458800
AND (
build_chroot.started_on > 1547458200
OR (build_chroot.started_on is NULL AND build_chroot.status = 4)
-- for currently pending builds we need to filter on status=pending because there might be
-- failed builds that have started_on=NULL
)
AND NOT build.canceled;
before
Planning time: 1.041 ms
Execution time: 188.590 ms
after
Planning time: 0.987 ms
Execution time: 0.864 ms