Re: Full text indexing preformance! (long)
От | Mitch Vincent |
---|---|
Тема | Re: Full text indexing preformance! (long) |
Дата | |
Msg-id | 003801bfcaa2$fb8d08e0$0300000a@doot.org обсуждение исходный текст |
Ответ на | Full text indexing preformance! (long) ("Mitch Vincent" <mitch@venux.net>) |
Список | pgsql-hackers |
> > Well, of course the whole *point* of LIMIT is that it stops short of > > scanning the whole query result. So I'm afraid you're kind of stuck > > as far as the performance goes: you can't get a count() answer without > > scanning the whole query. Right, that's what I thought. > > I'm a little curious though: what is the typical count() result from > > your queries? The EXPLAIN outputs you show indicate that the planner > > is only expecting about one row out now, but I have no idea how close > > that is to the mark. If it were really right, then there'd be no > > difference in the performance of LIMIT and full queries, so I guess > > it's not right; but how far off is it? Well, count does always return 1 row, though what's in that one row is as varying as 0 to the number of records in the applicants database (about 11,000).. Anyway, I thank you and appreciate your input.. -Mitch
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