Re: Performance on large, append-only tables

On Fri, Feb 10, 2012 at 1:45 PM, David Yeu  wrote:
> On Feb 10, 2012, at 11:26 AM, Claudio Freire wrote:
>> That, and an index on "(group_id, created_at) where (deleted_at IS
>> NULL)" to catch the sorted by date kind of query, and you'll be done I
>> think.
>
> Yeah, I didn't quite get that right -- we're actually sorting all these queries by "id DESC", not "created_at DESC", so that seems to obviate the need for any index on created_at.

From your OP:

>  * Š WHERE group_id = ? ORDER BY created_at DESC LIMIT 20;