Re: QUERY: autovacuum: VACUUM ANALYZE table versus QUERY: autovacuum: VACUUM table

On 11/1/19 7:49 PM, Jason Ralph wrote:
> Hello list,
> I am trying to find out if the naming convention from autovacuum does what its command line equivalent does, or at least what I think it does.
>
> QUERY: autovacuum: VACUUM ANALYZE table versus autovacuum: VACUUM ANALYZE table.

The above are the same, I'm guessing you are referring to 1) and 2) below.

>
> I have been getting my autovacuum tuned and I have the settings where I see 2 types of queries running now and doing their jobs. I know vacuum alone will mark dead tuples ready for use again, and analyze alone will update statistics for the query planner.
>
> 1. QUERY: autovacuum: VACUUM ANALYZE table
> 2. QUERY: autovacuum: VACUUM table
>
> My question is do we need both? Why wouldn't QUERY: autovacuum: VACUUM ANALYZE table perform both, I always thought when issuing VACUUM ANALYZE table it would do both. Why wouldn't we just want vacuum analyze to run?
> Or is QUERY: autovacuum: VACUUM ANALYZE table different from the command line and it only analyzes and QUERY: autovacuum: VACUUM table only vacuums which would make sense.

See here:
https://www.postgresql.org/docs/11/routine-vacuuming.html#AUTOVACUUM

"Each worker process will check each table within its database and
execute VACUUM and/or ANALYZE as needed"

In same section read sections on vacuum and analyze thresholds, which
determine the 'and/or' above.

The commands are the same. Autovacuum is just a background process that
calls the regular VACUUM/ANALYZE commands as needed.

>
>
> Thanks as always and hope this is clear.
>
>
> Jason Ralph
>
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--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com