Re: Query slows after offset of 100K - Mailing list pgsql-performance

From Tom Lane
Subject Re: Query slows after offset of 100K
Date
Msg-id 17159.1203016095@sss.pgh.pa.us
Whole thread Raw
In response to Query slows after offset of 100K  (Michael Lorenz <mlorenz1@hotmail.com>)
Responses Re: Query slows after offset of 100K  (Michael Lorenz <mlorenz1@hotmail.com>)
List pgsql-performance
Michael Lorenz <mlorenz1@hotmail.com> writes:
> My query is as follows:
> SELECT o.objectid, o.objectname, o.isactive, o.modificationtime
> FROM    object o
> WHERE  ( o.deleted = false OR o.deleted IS NULL )
> AND      o.accountid = 111
> ORDER BY 2
> LIMIT 20 OFFSET 10000;

This is guaranteed to lose --- huge OFFSET values are never a good idea
(hint: the database still has to fetch those rows it's skipping over).

A saner way to do pagination is to remember the last key you displayed
and do something like "WHERE key > $lastkey ORDER BY key LIMIT 20",
which will allow the database to go directly to the desired rows,
as long as you have an index on the key.  You do need a unique ordering
key for this to work, though.

            regards, tom lane

pgsql-performance by date:

Previous
From: Michael Lorenz
Date:
Subject: Query slows after offset of 100K
Next
From: Michael Lorenz
Date:
Subject: Re: Query slows after offset of 100K