Re: reducing statistics write overhead

Martin Pihlak escribió:
> Alvaro Herrera wrote:
> > You missed putting back the BUG comment that used to be there about
> > this.
>
> This was deliberate, I did mention the condition in the comment at
> the beginning of the file. This actually makes it a feature :)
>
> Seriously though, do you think that this is still a problem? Given
> the rare occurrence of the revacuum and the fact that it is made
> cheap by visibility map?

Hmm, maybe it's no longer an issue with the visibility map, yes.

> I was wondering that maybe the stats subsystem shouldn't be used for
> vacuum tracking at all. It maybe convenient to use, but has several
> deficiencies (pobig file, lossy, no crash safety, etc). Could we move
> vacuum tracking to pg_class instead?

I agree that pgstats is not ideal (we've said this from the very
beginning), but I doubt that updating pg_class is the answer; you'd be
generating thousands of dead tuples there.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.