Re: OFFSET and LIMIT - performance

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От Kaloyan Iliev
Тема Re: OFFSET and LIMIT - performance
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Msg-id 4684E012.9070709@digsys.bg
обсуждение исходный текст
Ответ на Re: OFFSET and LIMIT - performance  (Tom Lane <tgl@sss.pgh.pa.us>)
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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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