Re: Some ideas about Vacuum

Alvaro Herrera <alvherre@commandprompt.com> writes:
> Tom Lane escribió:
>> It would only be useful to have one per spindle-dedicated-to-WAL, so
>> tying the division to databases doesn't seem like it'd be a good idea.

> Keep in mind that there are claims that a write-cache-enabled
> battery-backed RAID controller negates the effect of a separate spindle.

Possibly true, but if that's the underlying hardware then there's no
performance benefit in breaking WAL up at all, no?

> My point, rather, is that with this sort of setup it would be easier to
> do per-database PITR shipping, and one database's WAL activity would not
> affect another's (thus hosting providers are happier -- high-rate
> customer A need not affect low-budget customer B).

You won't get far with that because of the shared catalogs.  In
particular, most DDL operations these days touch pg_shdepend ...
        regards, tom lane