Oracle Performance Firefighting
by Craig Shallahamer

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Craig Shallahamer's Blog

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The text below is an except from the book, Oracle Performance Firefighting, written by Craig Shallahamer of OraPub, Inc. Figures and tables are not included on this page, only their reference.
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©2009, 2010 by Craig Shallahamer. This is copyrighted material.
Please—Out of respect for those involved in the creation of the book and also for their familes, we ask you to respect the copyright both in intent and deed. Thank you.

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As with resolving shared pool latch contention, one solution to 4031 errors is to flush the shared pool. While no DBA wants to admit to periodically flushing a shared pool,4 this still works. Depending on the Oracle release, the amount of allocated shared pool memory, and the application's unique memory usage pattern, it may be your best bet. This is especially true for pre-Oracle 9i systems.

Increasing shared pool memory conceptually provides Oracle with more flexibility in satisfying memory requests. However, along with the benefits, there is always a cost when shifting computing resources. In most cases, the benefits actually do outweigh the costs, so if the operating system has the memory available, or if you can shift memory from other Oracle caches to the shared pool, increasing shared pool memory is highly likely to reduce 4031 errors.

Keep in mind that any time you ask Oracle to manage more memory, more CPU is required to manage that memory. This is especially true with pre-Oracle9i systems because of the potential for extremely long memory chain heaps. If the chains are thousands of chunks long, while 4031 errors may subside, the situation can manifest into serious shared pool latch contention and massive CPU consumption while attempting to acquire the shared pool latch and also while scanning the long chains-so be careful.

©2009, 2010 by Craig Shallahamer. This is copyrighted material.
Please—Out of respect for those involved in the creation of the book and also for their familes, we ask you to respect the copyright both in intent and deed. Thank you.


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