Re: how much ram do i give postgres?

On 19 Oct 2004 at 17:35, Josh Close wrote:

> Well, I didn't find a whole lot in the list-archives, so I emailed
> that list whith a few more questions. My postgres server is just
> crawling right now :(
>

Unlike many other database engines the shared buffers of Postgres is
not a private cache of the database data. It is a working area shared
between all the backend processes. This needs to be tuned for number
of connections and overall workload, *not* the amount of your database
that you want to keep in memory. There is still lots of debate about what
the "sweet spot" is. Maybe there isn't one, but its not normally 75% of
RAM.

If anything, the effective_cache_size needs to be 75% of (available)
RAM as this is telling Postgres the amount of your database the *OS* is
likely to cache in memory.

Having said that, I think you will need to define "crawling". Is it
updates/inserts that are slow? This may be triggers/rules/referential
integrity checking etc that is slowing it. If it is selects that are slow, this
may be incorrect indexes or sub-optimal queries. You need to show us
what you are trying to do and what the results are.

Regards,
Gary.