Re: How to simulate latch: cache buffers chains and latch: row cache objects

From: kunwar singh <krishsingh.111_at_gmail.com>
Date: Wed, 28 Aug 2019 22:34:13 -0400
Message-ID: <CAJSrDUpNeqqMktWgy==2sG_K7uEgZnjTg2-mE8SyuFa1nCQ=iQ_at_mail.gmail.com>



Thanks Noveljic! I will try these

On Tue, Aug 27, 2019 at 2:39 AM Noveljic Nenad <nenad.noveljic_at_vontobel.com> wrote:

> Actually, there’s a brilliant presentation on latch internals by Andrey
> Nikolaev:
> https://andreynikolaev.files.wordpress.com/2012/12/andrey_nikolaev_latch_internals_2012_for_ruoug.pdf
>
>
>
> He provides the information on the functions which request and allocate
> the latches as well as the instructions how to allocate a latch by calling
> these functions. Oradebug call inside sqlplus might not work anymore, but
> you can easily accomplish the same by using gdb.
>
>
>
> There’s also code in there for reproducing row cache objects contention.
>
>
>
> Best regards,
>
>
>
> Nenad
>
>
>
>
>
>
>
> *From:* oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org> *On
> Behalf Of *Noveljic Nenad
> *Sent:* Dienstag, 27. August 2019 07:00
> *To:* krishsingh.111_at_gmail.com; ORACLE-L <oracle-l_at_freelists.org>
> *Subject:* RE: How to simulate latch: cache buffers chains and latch: row
> cache objects
>
>
>
> To reproduce a latch at will and hold it for deterministic time period I
> would set the breakpoint with gdb on a function participating in latch
> allocation.
>
>
>
> To get an idea which functions that might be I’d gather stack traces when
> the latch event gets written into the 10046 trace files. This is something
> that can be accomplished with either DTrace or gdb. I described the method
> with DTrace here:
> https://nenadnoveljic.com/blog/enriching-trace-with-call-stacks/
>
>
>
> Best regards,
>
>
>
> Nenad
>
>
>
> _at_NenadNoveljic
>
>
>
>
>
> *From:* oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org> *On
> Behalf Of *kunwar singh
> *Sent:* Montag, 26. August 2019 22:40
> *To:* ORACLE-L <oracle-l_at_freelists.org>
> *Subject:* How to simulate latch: cache buffers chains and latch: row
> cache objects
>
>
>
> Hi Listers,
>
> Just an academic question.
>
>
>
> I am trying to learn about these wait events in detail.
>
> Can you please share what how i can reproduce it on a 12.2 or higher DB
>
>
>
> i have a test machine with 24 cores and 12.2 DB running on it.
>
>
>
> --
>
> Cheers,
> Kunwar
>
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-- 
Cheers,
Kunwar

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Received on Thu Aug 29 2019 - 04:34:13 CEST

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