Red Hat CLUSTER SUITE FOR ENTERPRISE LINUX 5.1 Installation Guide download pdf (Page 38)

The Oracle SGA (Shared Global Area) contains several memory structures that used to improve the

performance of the executing SQL. The largest, and most critical is the db block buffer cache. This cache

typically consumes over 80% of the SGA. Several SQL pools used for results and complex parallel

operations consume the next largest block.

The advent of x64 systems make it possible to SGA ranges in the 8-1024GB range. For any SGA that is

over 16GB, a consistent improvement of 8-15% should be possible; the larger the SGA, the more the

improvement. In addition to making it possible for the hardware to do less work when providing memory

to the RDBMS, it also saves user memory by reducing the number of process page table entries (T LBs)

that must be stored by each process.

For information on optimizing SGA settings, consult your Oracle user guide.

Chapter 4. RAC/GFS Cluster Configuration

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Red Hat CLUSTER SUITE FOR ENTERPRISE LINUX 5.1 Installation Guide Page 38