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However, simply dividing a large single list into smaller lists may not always work. It depends on how the memory structure is accessed. The Oracle kernel architects must ensure deadlock-type situations are unlikely, and if they do occur, they are recoverable. Oracle architects should know (and we really hope they do) that this particular situation was well suited for a simple multiple-latch solution.
The cache buffer chain (CBC) structure is used to quickly answer the question, "Is the Oracle block in the buffer cache?" Thinking about all the Oracle systems in the world today, the number of times this question is asked each day is mind-boggling.
The CBC is essentially a searching structure. There are many search algorithms for Oracle to choose from, but for reasons I'll detail in Chapter 6, Oracle chose what is known as a hashing structure. Figure 3-5 is an example of a hashing structure.
©2009, 2010 by Craig Shallahamer. This is copyrighted material.
PleaseOut 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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