Re: v$access + latch free(library cache) BUG???

Hello Syed,

Any access to V$ACCESS on an instance with 1000+ connections creates at least short term contention for the library cache latches. That is not a bug. It is a consequence of all the work that is needed to instantiate the view. With your system already suffering contention for another latch, it is not strange that any reference to V$ACCESS would induce severe library cache latch contention. In short, I don't think that this is a bug.

@   Regards,
@   Steve Adams
@   http://www.ixora.com.au/         - For DBAs
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The Human Fly wrote:
> Hello list,
>
> We have faced a very very strange problem when accessing or desc v$access table.
>
> Database : Oracle 9i Rel.2 (9205)
> OS : AIX 5.3 JFS2 Filesystem.
> CPU = 30+
> No. Connections = 1000+
>
> We are facing problem with latch free (cache buffer chains), when the
> problem occurs, cpu becomes 0% ideal and we kill some process from
> which transaction are coming.
>
> I just desc v$access from the sql prompt, and strangly, all the
> session are started waiting on 'latch free' and this time its was
> library cache and when I kill the session which was desc v$access,
> then, everything comes normal.
>
> It was not just an accident, I can still reproduce the same error.
> Whatever action I do on v$access, this is causing. If this was a bug,
> we have same OS server, same oracle version for another database,
> where this doesn't happens. The only differene between these two
> databases are just no. of cpus.
>
> It is really drawing me crazy. Does anyone has experience the same?
>
> --
> Best Regards,
> Syed Jaffar Hussain

[snip]

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