"Gnanakumar" <gnanam@zoniac.com> writes:
>> Has your Postgres instance crashed or been restarted with immediate mode
>> since the last vacuum? This will cause the autovacuum information to be
>> null.
> No, it's been up and running for almost a week. I even checked with "select
> pg_postmaster_start_time()".
I don't believe pg_postmaster_start_time() is reset by a
backend-crash-and-restart sequence ... but the stats collector data will
be. You might want to look into the postmaster log for evidence of
such a crash.
regards, tom lane