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Multiple Oracle buffer LRU latches?
Oracle Tips by Burleson Consulting |
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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