2011/6/23 Gábor Farkas <gabor@xxxxxxxxxxxxxx>: > 2011/6/23 Thom Brown <thom@xxxxxxxxx>: >> 2011/6/23 Gábor Farkas <gabor@xxxxxxxxxxxxxx>: >>> hi, >>> >>> postgresql8.4.7 here. >>> >>> i checked the pg_stat_user_tables table, and it have a lot of rows >>> there where the "last_autovacuum" and/or "last_autoanalyze" are null. >>> does this mean that autovacuum never worked on those tables? >>> >>> roughly 70% of all the tables have null in those fields.. >>> in those never-autovacuumed tables there are tables that are quite >>> big, and also have a lot of activity, so it's not that they never >>> needed vacuuming... >>> >>> i wonder why autovacuum ignored them. i checked my settings with "SHOW >>> ALL" in psql, and the corresponding settings are: >>> >>> autovacuum on >>> autovacuum_analyze_scale_factor 0.1 >>> autovacuum_analyze_threshold 50 >>> autovacuum_freeze_max_age 200000000 >>> autovacuum_max_workers 3 >>> autovacuum_naptime 1min >>> autovacuum_vacuum_cost_delay 20ms >>> autovacuum_vacuum_cost_limit -1 >>> autovacuum_vacuum_scale_factor 0.2 >>> autovacuum_vacuum_threshold 50 >>> track_counts on >>> >>> any ideas why autovacuum ignores some of the tables? >> >> The table may have not had enough updates or deletes to trigger a >> vacuum. Are these insert-only tables? When you look at >> pg_stat_user_tables, check the n_tup_upd and n_tup_del columns. >> >> If autovacuum_vacuum_threshold + (autovacuum_vacuum_scale_factor * >> rows in the table) > n_dead_tup in pg_stat_user_tables, then the table >> should be autovacuum'd. If it hasn't yet reached this number, it >> won't yet be a candidate. > > thanks for the explanation, now i understand. just to clarify: you > probably meant > the opposite, correct? when n_dead_tup is MORE than the threshold... Erk, yes, switch the > to a <. -- Thom Brown Twitter: @darkixion IRC (freenode): dark_ixion Registered Linux user: #516935 EnterpriseDB UK: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
