Re: way to speed up a SELECT DISTINCT?
От | Seth Ladd |
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Тема | Re: way to speed up a SELECT DISTINCT? |
Дата | |
Msg-id | 9BE142FC-FB0F-11D7-A8D2-000A9576D038@picklematrix.net обсуждение исходный текст |
Ответ на | Re: way to speed up a SELECT DISTINCT? (Peter Childs <blue.dragon@blueyonder.co.uk>) |
Ответы |
Re: way to speed up a SELECT DISTINCT?
Re: way to speed up a SELECT DISTINCT? Re: way to speed up a SELECT DISTINCT? |
Список | pgsql-performance |
>> Is there any way to speed this up, or is that DISTINCT going to keep >> hounding me? >> >> I checked the mailing list, and didn't see anything like this. >> >> Any tips or hints would be greatly appreciated. Thanks for your help! >> Seth >> >> > Try group by instead. I think this is an old bug its fixed in > 7.3.2 which I'm using. > > Peter Childs > ` > > > peter@bernardo:express=# explain select distinct region from region; > QUERY PLAN > ----------------------------------------------------------------------- > ----------------------- > Unique (cost=0.00..4326.95 rows=9518 width=14) > -> Index Scan using regionview_region on region > (cost=0.00..4089.00 > rows=95183 width=14) > (2 rows) Thanks for the tip, I'll give this a shot soon. I am curious, your example above does not use GROUP BY yet you have an INDEX SCAN. I am using a similar query, yet I get a full table scan. I wonder how they are different? I'll try the group by anyway. Thanks, Seth
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