Re: OFFSET and LIMIT - performance
От | Kaloyan Iliev |
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Тема | Re: OFFSET and LIMIT - performance |
Дата | |
Msg-id | 4684E012.9070709@digsys.bg обсуждение исходный текст |
Ответ на | Re: OFFSET and LIMIT - performance (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-general |
And what about using cursors and move. Which is faster - OFFSET/LIMIT OR CURSOR/MOVE. Best Regards, Kaloyan Iliev Tom Lane wrote: >"Jan Bilek" <bilekj@gmail.com> writes: > > >>I'm using PGDB with JDBC. In my app i need to select only portion of all = >>available rows. I know i can do it two ways: >>1. I can use OFFSET and LIMIT SQL statements or >>2. I can select all rows and then filter requested portion in Java. >> >> > > > >>My question - Does the second way significantly affect performance = >>especially when used with JDBC? >> >> > >Network transmission costs alone would make the second way a loser. > >Large OFFSETs are pretty inefficient because the backend generates and >discards the rows internally ... but at least it never converts them to >external form or ships them to the client. Rows beyond the LIMIT are >not generated at all. > > regards, tom lane > >---------------------------(end of broadcast)--------------------------- >TIP 2: Don't 'kill -9' the postmaster > > >
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