Re: BUG #6068: automatic analyze runs endlessly

The following bug has been logged online:

Bug reference: 6068
Logged by: Jeff Janes
Email address: jeff(dot)janes(at)gmail(dot)com
PostgreSQL version: 9.1beta1
Operating system: Linux
Description: automatic analyze runs endlessly
Details:

Starting with commit b4b6923e03f4d29636a94f6f4cc2f5cf6298b8c8,
"Fix VACUUM so that it always updates pg_class.reltuples/relpages."

After running make installcheck, the tables regression.public.slow_emp4000
and regression.public.fast_emp4000 get analyzed once a minute even though
they have no activity. None of the other installcheck tables, just those
two.

This has no direct negative effect that I know of, but it seems to be a
worrying symptom that pg_class or some related entity may not be getting
updated correctly.

"Jeff Janes" <jeff(dot)janes(at)gmail(dot)com> writes:
> Starting with commit b4b6923e03f4d29636a94f6f4cc2f5cf6298b8c8,
> "Fix VACUUM so that it always updates pg_class.reltuples/relpages."

> After running make installcheck, the tables regression.public.slow_emp4000
> and regression.public.fast_emp4000 get analyzed once a minute even though
> they have no activity. None of the other installcheck tables, just those
> two.

> This has no direct negative effect that I know of, but it seems to be a
> worrying symptom that pg_class or some related entity may not be getting
> updated correctly.

Hmm ... seems worrisome, all right, but I don't see that happening here.
At least I don't see any indication of it in
pg_stat_all_tables.last_autoanalyze. Are you looking at that, or some
other evidence? Do you have any nondefault settings?

regards, tom lane

"Jeff Janes" <jeff(dot)janes(at)gmail(dot)com> writes:
> After running make installcheck, the tables regression.public.slow_emp4000
> and regression.public.fast_emp4000 get analyzed once a minute even though
> they have no activity. None of the other installcheck tables, just those
> two.

Oh, wait, I see what's different about those two tables: they have no
analyzeable columns. I thinko'd what to do in that situation. Will
fix.

regards, tom lane

On 6/19/11, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> "Jeff Janes" <jeff(dot)janes(at)gmail(dot)com> writes:
>> Starting with commit b4b6923e03f4d29636a94f6f4cc2f5cf6298b8c8,
>> "Fix VACUUM so that it always updates pg_class.reltuples/relpages."
>
>> After running make installcheck, the tables regression.public.slow_emp4000
>> and regression.public.fast_emp4000 get analyzed once a minute even though
>> they have no activity. None of the other installcheck tables, just those
>> two.
>
>> This has no direct negative effect that I know of, but it seems to be a
>> worrying symptom that pg_class or some related entity may not be getting
>> updated correctly.
>
> Hmm ... seems worrisome, all right, but I don't see that happening here.
> At least I don't see any indication of it in
> pg_stat_all_tables.last_autoanalyze. Are you looking at that, or some
> other evidence? Do you have any nondefault settings?

Just log_autovacuum_min_duration=0

Both evidence and setting.

Cheers, Jeff