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On Mon, May 24, 2021 at 04:19:01PM +0530, sreekanth vajrapu wrote: > Hi Team, > > We are having a slow query issue for one of our applications. We are seeing > slowness(5 seconds) when we use both ORDER BY and LIMIT 30 clause whereas > the same query is performing very good(200 MS) when using only ORDER BY > clause. Also note that the query performed very fast(200 MS) when we > increased LIMIT to 100 along with ORDER BY. > > Can you please help us if there are any bugs related to this? OR Can > someone kindly provide some solution to this issue? This is not at base a bug. Instead, it's a behavior which compliance with the SQL standard mandates. You're doing pagination, and unfortunately you're doing it in a way that, while it appears simple and intuitive, guarantees poor performance for later pages. Here's a concise description of the fundamental problem you're encountering along with some suggestions as to how to do this more efficiently, i.e. faster consistently. https://use-the-index-luke.com/no-offset Here are some more references on pagination and how to do it efficiently: http://www.depesz.com/2007/08/29/better-results-paging-in-postgresql-82/ https://wiki.postgresql.org/wiki/File:Pagination_Done_the_PostgreSQL_Way.pdf https://coderwall.com/p/lkcaag https://www.citusdata.com/blog/2016/03/30/five-ways-to-paginate/ https://ask.use-the-index-luke.com/questions/205/how-to-query-for-previous-page-with-keyset-pagination Best, David. -- David Fetter <david(at)fetter(dot)org> http://fetter.org/ Phone: +1 415 235 3778 Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate
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