Why is my table not autovacuuming?

PostgreSQL 9.2.18. I have a table with 71M rows (via select count). In
pg_stat_activity, n_live_tups is 170K, n_dead_tups is slightly more than
that (203K). The autovacuum parameter is on, the scale factor is 0.2
(default) and threshold is 50 (default), autovacuum_max_workers is 3. There
are no custom autovacuum thresholds set for this table. The last_autovacuum
field is null.

Obviously I would expect autovacuum/autoanalyze to kick in for this table
so the stats aren't getting so far out of whack from reality. When I query
pg_stat_activity, I never see any autovacuum jobs running, so it isn't a
matter of too much work from what I can tell.

Previously I had tables not being autovacuumed because of index corruption
(which would also cause manual vacuum to fail), but I was just able to
successfully vacuum this table manually and now pg_stat_activity show the
accurate info.

Wondering why my autovacuum daemon appears to be acting lazily?

Don.

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Don Seiler
www.seiler.us