On Fri, Mar 17, 2017 at 9:37 PM, Jeff Janes <jeff.ja...@gmail.com> wrote: > With some intensive crash-recovery testing, I've run into a situation where > I get some bad table bloat. There will be large swaths of the table which > are empty (all results from heap_page_items other than lp are either zero or > NULL), but have zero available space in the fsm, and are marked as > all-visible and all-frozen in the vm. > > I guess it is a result of a crash causing updates to the fsm to be lost. > Then due to the (crash-recovered) visibility map showing them as all visible > and all frozen, vacuum never touches the pages again, so the fsm never gets > corrected.
I guess that this happens only if heap_xlog_clean applies FPI. Right? Updating fsm can be lost but fsm is updated by replaying HEAP2_CLEAN record during crash recovery. > > 'VACUUM (DISABLE_PAGE_SKIPPING) foo;' does fix it, but that seems to be > the only thing that will. If the above is correct, another one option is to allow heap_xlog_clean to update fsm even when appling FPI. Regards, -- Masahiko Sawada NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
