Re: Indexing problem with OFFSET LIMIT

"Merlin Moncure" <mmoncure(at)gmail(dot)com> writes:
> On Fri, Aug 29, 2008 at 4:38 PM, Oliver Weichhold <oliver(at)weichhold(dot)com> wrote:
>> Consider this query:
>>
>> SELECT * FROM foo WHERE realm_id = 228 order by foo_name LIMIT 200 OFFSET
>> 15000

> try this:
> SELECT * FROM foo WHERE realm_id = 228 order by realm_id, foo_name
> LIMIT 200 OFFSET
> 15000

> Or even better don't use 'offset' at all. It's simply lousy. If
> you want to skip ahead 200 rows at a time, save off the previous last
> extracted rows in the app:

Yeah, large OFFSET values are always going to suck performance-wise,
because there is no magic way to skip over those rows --- the backend
has to read them, and then throw them away internally. Avoid OFFSET.

Aside from the type of trick Merlin mentions, have you considered using
a cursor?

regards, tom lane