Tom Lanyon <tom+pgsql-ad...@oneshoeco.com> writes: > I'm seeing a heavy-update TOAST table which is not being effectively > autovacuum'd on 8.4.5. The stats collector shows n_dead_tup growing very > quickly, and autovacuum runs frequently, but never removes any dead tuples. > A manual vacuum does find many dead tuples (90+ % of the table) to remove, > and removes them properly.
Is autovacuum actually running against the toast table? Check the last_autovacuum column in pg_stat_all_tables. If not, and if pg_class' relpages/reltuples columns seem pretty out of date for the toast table, this might be a variant of the problem reported here: http://archives.postgresql.org/pgsql-admin/2011-05/msg00101.php which was patched here: http://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=b503da135ab0bdd97ac3d3f720c35854e084e525 although that patch hasn't actually made it into any shipping release yet :-( I'm not entirely convinced that you're seeing a related issue, because Florian was complaining of too many autovacuums not too few, but if you cross your eyes a bit and assume the symptom is "poor autovacuum scheduling" then maybe the same problem explains both. Another post-8.4.5 bug fix that could affect autovacuum's promptness is http://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=fab2af30d6bb4ca893e2e9bf96863e6f1ce826d2 > Whilst debugging, I found that there seems to be a large amount of the old > 'PD_ALL_VISIBLE incorrectly set...' warnings emitted during the autovacuum > run. If that were the issue, manual vacuums would be subject to it too. regards, tom lane -- Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
