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Re: limit + order by is slow if no rows in result set
- From: Heikki Linnakangas <heikki(at)enterprisedb(dot)com>
- To: Brian Cox <brian(dot)cox(at)ca(dot)com>
- Cc: pgsql-performance(at)postgresql(dot)org
- Subject: Re: limit + order by is slow if no rows in result set
- Date: Mon, 12 Feb 2007 23:26:04 +0000
Brian Cox wrote:
There are 1.9M rows in ts_defects and indexes on b.ts_id (primary key)d.ts_biz_event_id and d.ts_occur_date. Both queries below return 0 rows. The 1st runs fast and the 2nd > 400x slower. The 2nd querydiffers from the 1st only by the addition of "limit 1". Why the big difference in performance?
Please run EXPLAIN ANALYZE on both queries, and send back the results. Also, what indexes are there on the tables involved?
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com
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- From: Brian Cox
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