Re: Optimization via explicit JOINs
| От | Stephan Szabo |
|---|---|
| Тема | Re: Optimization via explicit JOINs |
| Дата | |
| Msg-id | Pine.BSF.4.21.0103091817560.82859-100000@megazone23.bigpanda.com обсуждение исходный текст |
| Ответ на | Re: Optimization via explicit JOINs (David Olbersen <dave@slickness.org>) |
| Ответы |
Re: Optimization via explicit JOINs
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| Список | pgsql-sql |
Actually, just thought of something else. If you remove the probably redundant p.song_id=s.song_id from the second query (since the join ... using should do that) does it change the explain output? On Fri, 9 Mar 2001, David Olbersen wrote: > On Fri, 9 Mar 2001, Stephan Szabo wrote: > > ->As a question, how many rows does > ->select * from playlist p join songs s using (song_id) where > ->p.waiting=TRUE; > ->actually result in? > > Well it depends. Most of the time that playlist table is "empty" (no rows where > waiting = TRUE), however users can (in a round about way) insert into that > table, so that there could be anywhere from 10, to 2,342, to more. > > Why do you ask? > > (The reason those plans chose 14 was because, at the time, there were 14 rows in > playlist)
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