If you are manually managing the shared pool and you??™ve diagnosed which of these
problems is occurring, the solution is fairly simple: increase the size of the shared
pool using the SHARED_POOL_SIZE initialization parameter. Shared pool sizes in
the 150??“250 MB range are not uncommon for large, active databases. For more
information about examining shared pool activity to identify problems, see the
appropriate Oracle Performance Tuning Guide, as well as the third-party books listed
in Appendix B.
The redo log buffer
While the redo log buffer consumes a very small amount of memory in the SGA relative
to the database buffer cache and the shared pool, it??™s critical for performance.
Transactions performing changes to the data in the database write their redo information
to the redo log buffer in memory. The redo log buffer is flushed to the redo
logs on disk when a transaction is committed (normally) or when the redo log buffer
is one-third full. Oracle ???fences??? off the portion of the redo log buffer that??™s being
flushed to disk to make sure that its contents aren??™t changed until the information is
safely on disk.
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