Shulou(Shulou.com)06/01 Report--

Enter SQLPLUS, query shared_pool, and often see the following results:

SQL> show parameter shared_pool

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

shared_pool_reserved_size big integer 20971520

shared_pool_size big integer 419430400

In Oracle, shared_pool consists of two parts, one of which is shared_pool_reserved_size. This parameter is used to specify the amount of shared pool space reserved to accommodate future large sequential requests for shared pool space. When the shared pool is too fragmented, requesting large chunks of space will cause Oracle to extensively find and free shared pool memory to satisfy the request, which may cause severe performance degradation. By setting the appropriate shared_pool_reserved_size parameter, combined with the shared_pool_reserved_min_alloc parameter, you can avoid the performance degradation caused by this.

The ideal value for this parameter should be large enough to satisfy any memory request for RESERVED LIST without the database flushing objects from the shared pool. The default value for this parameter is 5% of the shared_pool_size, and the recommended value for this parameter is usually 10% to 20% of the shared_pool_size parameter, with a maximum of 50% of the shared_pool_size. (More than 50% may cause the database to fail to start, be careful!)

rac system modification operation (the following modifications are recommended on databases without SGA enabled, and not recommended on databases with SGA enabled)

1. Modify the first node:

alter system set shared_pool_size=5000M sid='rac1' scope=spfile;

alter system set shared_pool_reserved_size=500M sid='rac1' scope=spfile;

shutdown immediate

startup

2. After the first node is started, modify the second node:

alter system set shared_pool_size=5000M sid='rac2' scope=spfile;

alter system set shared_pool_reserved_size=500M sid='rac2' scope=spfile;

shutdown immediate

startup

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