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Re: Oracle ODBC driver Pre-fetch problem with 8.1.78 Driver

From: Nick Palmer <nick_at_kcicorp.com>
Date: Tue, 6 May 2003 10:19:26 -0700
Message-ID: <vbfrk7705s5d3f@corp.supernews.com>


Norman,

Which version of the Oracle ODBC drivers are you using ?

My version - 9.0.1.6.0 (March 26, 2003) still has the pre-fetch buffer size, not a row count

Nick.

"Norman Dunbar" <Norman.Dunbar_at_lfs.co.uk> wrote in message news:E2F6A70FE45242488C865C3BC1245DA703A34E48_at_lnewton.leeds.lfs.co.uk...
> Hi Nick,
>
> Oracle's own ODBC driver for 8i and 9i relaese 2 both use pre-fetch
> counters, so you pre-fetch a number of rows from all tables and not a
> buffer size worth of rows. Microsoft's (broken) ODBC driver does it by
> setting up a buffer to read as many rows into as possible. Are you sure
> you have the Oracle driver in use ?
>
> The default for Oracle's driver is now (9i) 10 rows, but I've seen it
> being set to 1 row - which isn't much of a pre-fetch. I'm pretty certain
> that it all maps down to the OCI attributes for a statement
> OCI_ATTR_PREFETCH_ROWS and OCI_ATTR_PREFETCH_MEMORY according to
> whichever ODBC driver you are using. I've not used the 8178 driver
> myself so I cannot comment on whether it has changed from prefetch rows
> to a prefetch buffer, however, the 9i one has gone back/stayed at
> prefetch rows.
>
> The 64000 default you mention is almost 64K, but not quite. 65536 would
> be 64Kb.
>
>
> Cheers,
> Norman.
>
> -------------------------------------
> Norman Dunbar
> Database/Unix administrator
> Lynx Financial Systems Ltd.
> mailto:Norman.Dunbar_at_LFS.co.uk
> Tel: 0113 289 6265
> Fax: 0113 289 3146
> URL: http://www.Lynx-FS.com
> -------------------------------------
>
>
>
>
> -----Original Message-----
> From: Nick Palmer [mailto:nick_at_kcicorp.com]
> Posted At: Saturday, May 03, 2003 12:50 AM
> Posted To: server
> Conversation: Oracle ODBC driver Pre-fetch problem with 8.1.78 Driver
> Subject: Oracle ODBC driver Pre-fetch problem with 8.1.78 Driver
>
>
> Hi all,
>
> I'm having a strange problem with my Oracle ODBC Driver. I had the
> Oracle
> 8.1.74 ODBC driver on my system, and I upgraded to the 8.1.78 driver.
> After
> doing this, I noticed that my network packet count has gone up doing
> simple
> queries. It seems with this driver, that the driver is not pre-fetching
> any
> data. I also noted that in the 8.1.78 driver that the prefetch count
> has
> been replace by a prefetch buffer size. Is there a bug with the 8.1.78
> ODBC
> driver ?
> Or do I have to configure the Pre-fetch buffer size differently than the
> Pre-fetch count ? I've left the size at the default of 64000 - I
> assuming
> that means 64000 bytes = 64K.
>
> Thanks,
> Nick.
>
>
>
Received on Tue May 06 2003 - 12:19:26 CDT

Original text of this message

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