Re: TKPROF Output Explanation

From: Niall Litchfield <niall.litchfield_at_dial.pipex.com>
Date: 23 Mar 2005 02:01:10 -0800
Message-ID: <1111572000.321227.109760@f14g2000cwb.googlegroups.com>

Jonathan Lewis wrote:
> There are some front-end tools that
> generate code to pre-parse SQL so
> that they can build the appropriate
> memory structure for the anticipated
> data.
>
> In most cases, these reveal themselves
> with tkprof outputs that show two
> parses per execute.
>
> Perhaps you have a slightly more extreme
> case where some such tool has pre-parsed
> everything in a module 'just in case', but
> just doesn't happen to use some specific
> piece of SQL to collect data.

ODBC can definitely do it. It is, I think, done by issuing the SQLDescribeCol ODBC call after preparing a statement, but before executing it. We have an application that parses the statement "select <collist> from tab where...." but then executes (getting a second parse) "select rowid,<collist> from tab where ..." Still thats what CPUs and network bandwidth are for, right?

I actually want to work up a little worked example non how to do this better to send to the vendor, if anyone knows of any good ODBC Programming resources other than MSDN I'd love to see them.

Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com Received on Wed Mar 23 2005 - 04:01:10 CST