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Re: Suggestions Needed: Latch free - library cache

From: Jonathan Lewis <>
Date: Thu, 08 Jan 2004 01:54:27 -0800
Message-ID: <>

There's a failure in the statistics at this point. As far as I can tell, there are at least four different reasons why the stats can report a

    parse count (total)
without recording a

    parse count (hard)
and it would be nice if we could see them as four different statistics.

Code that explicit holds a cursor open need not issue a parse call at all.

Code that issues a parse call may:

    Invoke the whole parse/optimize cycle     Invoke a permissions cycle on an existing statement     Invoke a search and execute cycle on an existing statement with valid permission

    Invoke a 'this is where it is and I know I've got permission, so just do it' cycle

The last option can appear when you set up

    session_cached_cursors != 0.

The front-end code is still issuing an explicit parse call, which is why you see the parse count go up, but the work done is kept to near minimum.

NOTE: This description is probably not complete and I'd welcome any corrections and refinements that anyone can supply.


Jonathan Lewis

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> if your caching the cursors, why does soft parsing still happen?
> ----- Original Message -----
> To: "Multiple recipients of list ORACLE-L" <>
> Sent: Wednesday, January 07, 2004 7:24 PM

Please see the official ORACLE-L FAQ:
Author: Jonathan Lewis

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Received on Thu Jan 08 2004 - 03:54:27 CST

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