Re: Auto-tuning work_mem and maintenance_work_mem

On Wed, Oct 16, 2013 at 5:14 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> On 10/16/2013 01:25 PM, Andrew Dunstan wrote:
>> Andres has just been politely pointing out to me that my knowledge of
>> memory allocators is a little out of date (i.e. by a decade or two), and
>> that this memory is not in fact likely to be held for a long time, at
>> least on most modern systems. That undermines completely my reasoning
>> above.
>
> Except that Opensolaris and FreeBSD still have the old memory allocation
> behavior, as do older Linux kernels, many of which will remain in
> production for years. I have no idea what Windows' memory management
> behavior is.
>
> So this is a case of needing to know considerably more than the
> available RAM to determine a good setting.

I agree, but I still think my previous proposal of increasing the
defaults for work_mem and maintenance_work_mem by 4X would serve many
more people well than it would serve poorly. I haven't heard anyone
disagree with that notion. Does anyone disagree? Should we do it?

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company