当启用自动共享内存管理功能时，内部调优算法会尝试根据工作负载确定共享池的最优大小。该算法通常通过随时间逐渐增加的方式收敛到目标值，但通常不会尝试缩小共享池，因为开放游标、固定PL/SQL包等因素阻止了资源粒度的释放。
When the automatic shared memory management feature is enabled, the internal tuning
algorithm tries to determine an optimal size for
the shared pool based on the workload. It usually converges on this value by
increasing in small increments over time. However, the internal tuning algorithm
typically does not attempt to shrink the shared pool, because the presence of open
cursors, pinned PL/SQL packages, and other SQL execution state in the shared pool
make it impossible to find granules that can be freed. Therefore, the tuning algorithm
only tries to increase the shared pool in conservative increments, starting from a
conservative size and stabilizing the shared pool at a size that produces the optimal
performance benefit.[@more@]
algorithm tries to determine an optimal size for
the shared pool based on the workload. It usually converges on this value by
increasing in small increments over time. However, the internal tuning algorithm
typically does not attempt to shrink the shared pool, because the presence of open
cursors, pinned PL/SQL packages, and other SQL execution state in the shared pool
make it impossible to find granules that can be freed. Therefore, the tuning algorithm
only tries to increase the shared pool in conservative increments, starting from a
conservative size and stabilizing the shared pool at a size that produces the optimal
performance benefit.[@more@]
来自 “ ITPUB博客 ” ，链接：http://blog.itpub.net/10599713/viewspace-996267/，如需转载，请注明出处，否则将追究法律责任。
转载于:http://blog.itpub.net/10599713/viewspace-996267/
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