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. -- 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
