Re: Speed Up Offset and Limit Clause

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От Jim C. Nasby
Тема Re: Speed Up Offset and Limit Clause
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Msg-id 20060517190400.GV26212@pervasive.com
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Ответ на Re: Speed Up Offset and Limit Clause  ("Craig A. James" <cjames@modgraph-usa.com>)
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On Tue, May 16, 2006 at 07:20:12PM -0700, Craig A. James wrote:
> >Why I want to use offset and limit is for me to create a threaded
> >application so that they will not get the same results.
>
> In order to return rows 10000 to 15000, it must select all rows from zero
> to 15000 and then discard the first 10000 -- probably not what you were
> hoping for.
>
> You might add a "thread" column.  Say you want to run ten threads:

Another possibility is partitioning the table. If you do that using
inheritance-based partitioning, you could just select directly from
different partition tables, which probably be even faster than using a
single table. The downside is it's more work to setup.
--
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461

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