Re: Auto-tuning work_mem and maintenance_work_mem

On Wed, Oct  9, 2013 at 05:01:24PM +0200, Pavel Stehule wrote:
>     FYI, this auto-tuning is not for us, who understand the parameters and
>     how they interact, but for the 90% of our users who would benefit from
>     better defaults.  It is true that there might now be cases where you
>     would need to _reduce_ work_mem from its default, but I think the new
>     computed default will be better for most users.
> 
> 
> 
> then we should to use as base a how much dedicated RAM is for PG - not shared
> buffers.

Yes, that was Josh Berkus's suggestion, and we can switch to that,
though it requires a new GUC parameter, and then shared_buffers gets
tuned on that.

I went with shared_buffers because unlike the others, it is a fixed
allocation quantity, while the other are much more variable and harder
to set.  I figured we could keep our 25% estimate of shared_buffers and
everything else would fall in line.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + Everyone has their own god. +