Re: Simple select, but takes long time
От
Tom Lane
Тема
Re: Simple select, but takes long time
Дата
Msg-id
29725.1200103878@sss.pgh.pa.us
Ответ на
Simple select, but takes long time (James DeMichele)
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Re: Simple select, but takes long time andrew@pillette.com
Re: Simple select, but takes long time Tom Lane <tgl@sss.pgh.pa.us>
"James DeMichele" writes: > I am having a really hard time trying to figure out why my simple > count(*) query is taking so long. I have a table with 1,296,070 rows in > it. There are 2 different types of information that each row has that I > care about: Hmm, the EXPLAIN output works out to about 5 msec per row, which is not too out of line for a lot of random-access disk fetches. I'm surprised the planner bothered with an indexscan for this --- I'd bet a seqscan might be faster, seeing you're having to read about 1% of the rows which will likely touch most pages of the table anyway. Or a bitmap indexscan might be even better. What do you get if you try the EXPLAIN ANALYZE with enable_indexscan = off? regards, tom lane
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