Jim Nasby wrote:
> On Feb 19, 2007, at 1:19 PM, Jeff Davis wrote:
>> You told PostgreSQL that you have 900MB available for
>> maintenance_work_mem, but your OS is denying the request. Try *lowering*
>> that setting to something that your OS will allow. That seems like an
>> awfully high setting to me.
>
> 900MB isn't that unreasonable if you're building indexes on a restore or
> something similar. I have run into issues when trying to set it much
> over 1G, though... on various OSes and platforms.
versions before 8.2 have some issues(mostly reporting bogus errors) with
very large settings for maintenance_work_mem. 8.2 and up are behaving
more sanely but I don't think they can actually make anything better
with values in the GB range.
Have you actually measured a performance improvment going beyond
250-350MB(that seemed about to be the sweet spot last I tested) or so
for index creation and friends ?
Stefan