On Fri, 2006-05-26 at 14:47 -0500, Jim C. Nasby wrote:
> But the meat is:
> -- work_mem --
> Scale 2000 20000
> not compressed 150 805.7 797.7
> not compressed 3000 17820 17436
> compressed 150 371.4 400.1
> compressed 3000 8152 8537
> compressed, no headers 3000 7325 7876
Since Tom has committed the header-removing patch, we need to test
not compressed, no headers v compressed, no headers
There is a noticeable rise in sort time with increasing work_mem, but
that needs to be offset from the benefit that in-general comes from
using a large Heap for the sort. With the data you're using that always
looks like a loss, but that isn't true with all input data orderings.
-- Simon Riggs EnterpriseDB http://www.enterprisedb.com