Re: reducing statistics write overhead

Tom Lane wrote:
> I never understood why autovacuum should need a particularly short fuse
> on the stats file age to start with.  If the launcher is launching
> multiple workers into the same database with only a few milliseconds
> between them, isn't the launcher pretty broken anyhow?  ISTM that stats
> files even several seconds old ought to be plenty good enough.
> 

I was thinking that the launcher should only request fresh stats at wakeup,
the workers could then reuse that file. This could be implemented by calling
pgstat_clear_snapshot only at launcher wakeup and setting max stats age to
to autovacuum_naptime for the workers.

This would effectively disable the table vacuum recheck though. If this is
OK, I'll start working on it.

regards,
Martin