Hi Ron
How do I know if my AUTOVACUUM is Reasonably-tuned ?
If your queries are as fast as they can be, given proper index support. 😉
Specifically, I'd look at pg_stat_all_tables columns relname, n_dead_tup, n_mod_since_analyze, GREATEST(last_vacuum, last_autovacuum) and GREATEST(last_analyze, last_autoanalyze).
Run your system query a few times with EXPLAIN (BUFFERS), then "vacuumdb --all", and then run the queries again with EXPLAIN (BUFFERS).
If they're the same speed, then your AUTOVACUUM settings are either Good Enough, or you got lucky and the tables were recently analyzed. If they're faster, then you need to reduce the AUTOVACUUM config variables.
These are my settings for our workload. YMMV.
autovacuum = on
autovacuum_max_workers = 4
autovacuum_vacuum_scale_factor = 0.015
autovacuum_vacuum_threshold = 50
autovacuum_vacuum_cost_delay = 4ms
autovacuum_vacuum_cost_limit = 1000
autovacuum_analyze_scale_factor = 0.015
autovacuum_analyze_threshold = 50
Med venlig hilsen
Peter Gram
Sæbyholmsvej 18
2500 Valby
Mobile: (+45) 5374 7107
Hello PostgreSQL Experts,
Do we perform postgres maintenance (vacuum/analyze/reindex) on pg_catalog tables?
Reasonably-tuned AUTOVACUUM config parameters should handle that for you.
