Re: Fun with WAIT Event "library cache: mutex X"

From: Gaja Krishna Vaidyanatha <>
Date: Thu, 8 Dec 2011 10:58:18 -0800 (PST)
Message-ID: <>

Hi Greg,
I am tempted to term the "fight back" as an "undocumented feature" :) In that case, we absolutely need to find a way to disable it -- call this our fight back :)  


Gaja Krishna Vaidyanatha,
CEO & Founder, DBPerfMan LLC

Phone - +1-650-743-6060 Insights:Tales of the Oak Table - Co-author:Oracle Performance Tuning 101 -

 From: Grzegorz Goryszewski <> To:
Cc: "" <>; "''" <> Sent: Thursday, December 8, 2011 10:49 AM Subject: Re: Fun with WAIT Event "library cache: mutex X"  

On 2011-12-08 19:24, Gaja Krishna Vaidyanatha wrote:
> But, I am still old school when it comes to buffer cache sizing, shared pool & other pools sizing. I believe it should be part of a DBA's job and should be automated ONLY in applications/databases that demonstrate consistent, predictable and static behavior in workloads. For more dynamic and inconsistent workloads, I personally would go with manual memory settings. It is worthwhile incurring the additional cost of allocating more memory for the required structures and gain stability and consistency in return. Plus, the CPU overhead of MMAN (if and where relevant) can be avoided.

Please consider, despite of disabling AMM Oracle still fights back via: *"SGA Re-Sizes <javascript:;> Occurring Despite AMM/ASMM Being Disabled (MEMORY_TARGET <javascript:;>/SGA_TARGET <javascript:;>=0) [ID 1269139.1]"



Received on Thu Dec 08 2011 - 12:58:18 CST

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