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.