"Peter A. Daly" <petedaly(at)ix(dot)netcom(dot)com> writes:
> Tom Lane wrote:
>> Increasing SORT_MEM would help the constant factor, however...
>>
> What is the most amount of SORT_MEM it makes sense to allocate?
I've never experimented with it, but certainly the standard default
(512K = 0.5M) is pretty small for modern machines. In a 2G machine
I might try settings around 100M-500M to see what works best. (Note
this is just for a one-off btree creation --- for ordinary queries you
need to allow for multiple sorts going on in parallel, which is one
reason the default sort_mem is not very large.)
regards, tom lane