Thread: pgsql: Repair VACUUM FULL bug introduced by HOT patch: the original way
pgsql: Repair VACUUM FULL bug introduced by HOT patch: the original way
From
tgl@postgresql.org (Tom Lane)
Date:
Log Message: ----------- Repair VACUUM FULL bug introduced by HOT patch: the original way of calculating a page's initial free space was fine, and should not have been "improved" by letting PageGetHeapFreeSpace do it. VACUUM FULL is going to reclaim LP_DEAD line pointers later, so there is no need for a guard against the page being too full of line pointers, and having one risks rejecting pages that are perfectly good move destinations. This also exposed a second bug, which is that the empty_end_pages logic assumed that any page with no live tuples would get entered into the fraged_pages list automatically (by virtue of having more free space than the threshold in the do_frag calculation). This assumption certainly seems risky when a low fillfactor has been chosen, and even without tunable fillfactor I think it could conceivably fail on a page with many unused line pointers. So fix the code to force do_frag true when notup is true, and patch this part of the fix all the way back. Per report from Tomas Szepe. Tags: ---- REL8_1_STABLE Modified Files: -------------- pgsql/src/backend/commands: vacuum.c (r1.317.2.6 -> r1.317.2.7) (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/vacuum.c?r1=1.317.2.6&r2=1.317.2.7)