Multiple Oracle buffer LRU latches?

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Don Burleson Blog

Multiple Oracle buffer LRU latches?

Oracle Database Tips by Donald Burleson

Question: I noted that the buffer initialization parameters have a second parameter value for LRU latches, like this:

BUFFER_POOL_KEEP = (28,2)

What are LRU latches exactly and how do I determine the number of LRU latches for a data buffer?

Answer: The LRU latches parm specifies the number of LRU latches to assign to the data buffer pool (assigned by Oracle based on the CPU count of the server), but note that the minimum number of buffers assigned to the pool is 50 times the number of assigned latches

When configuring LRU latches and DBWR processes, remember that the latches are assigned to the pools sequentially and to the DBWR processes in round-robin fashion. The number of LRU processes should be equal to or a multiple of the value of DBWR processes to ensure that the DBWR load is balanced across the processes.

For more details, see Inside Oracle LRU latches.

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