Re: Autovacuum on by default?

Peter Eisentraut wrote:
> Summarizing this thread, I see support for the following:
>
> - autovacuum set to on by default in 8.2.

Yes.

> - stats_row_level also defaults to on.

Yes.

> (Perhaps stats_block_level should also default to on so it's not inconsistent,
> seeing that everything else in on, too.)

I haven't followed this closely, but are all the other stats commands
other than block_level now on by default? In general I would vote to
keep it off if not needed just for performance reasons, though I haven't
measured the effect of block_level turned on. Anyone measured this?

> - Delayed vacuum and delayed autovacuum will stay disabled.

Unfortunately.

> - Scale factor set to 0.08 (vacuum) and 0.04 (analyze) (?) (formerly 0.4 and
> 0.2)

That seems a big jump. BTW, I know .08 and .04 were suggested, but I
didn't see confirmation that it was a good idea. I know my initial
values were grossly over-conservative, but I am concerned about bogging
down the server with lots of vacuums, especially since we don't have the
delay settings on by default, nor do we have a maintenance windows yet.

> - Leave base thresholds alone (pending further analysis that might remove them
> altogether?)

While there is talk of removing this all together, I think it was also
agreed that as long as these values are there, they should be reduced.
I think the defaults in 8.1 are 1000/500, I think 200/100 was suggested.