RE: Read by other session and db sequential read waits

From: Siddiqui, Younus <younus.siddiqui_at_eds.com>
Date: Thu, 16 Oct 2008 01:17:19 -0400
Message-ID: <DE8F7694EDC1624C8F353A258392EF7D030784C2@usahm212.amer.corp.eds.com>


Forgot to mention that the problem disappears immediately if we cause the sql in question to hard parse - either flushing the shared pool or adding a hint
> _____________________________________________
>
> We have a 4-node Linux x86-64 cluster running 10.2.0.4 (CRS, ASM and
> DB). For the last one week we are running into a strange issue.
> One of SQLs which usually executes in under a sec suddenly starts
> running into db sequential and read by other session waits.
> We have outline hints to make sure the execution plan is not changing
> and to eliminate sql related issues.
>
> The problem occurs on only one node and so far it has it every node
> randomly.
>
> Checked for hot-block contention. Came up with only one with TCH of 50
> with more than thousand calls.
>
> The read by other session and db sequential read p1, p2 values change
> every second to point to different datafiles and blocks from user's
> default TS.
>
> Any help in identifying the issue or pointing in the right direction
> will be appreciated very much. I am working with OSS as well on this.
>
> Thank you,
> Younus
>
>
>

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Received on Thu Oct 16 2008 - 00:17:19 CDT

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