Property Description
Parameter type Big integer
Syntax SGA_TARGET = integer [K | M | G]
Default value 0 (SGA autotuning is disabled)
Range of values 64 to operating system-dependent
Basic Yes

SGA_TARGET specifies the total size of all SGA components. If SGA_TARGET is specified, then the following memory pools are automatically sized:

  • Buffer cache (DB_CACHE_SIZE)

  • Shared pool (SHARED_POOL_SIZE)

  • Large pool (LARGE_POOL_SIZE)

  • Java pool (JAVA_POOL_SIZE)

  • Streams pool (STREAMS_POOL_SIZE)

If these automatically tuned memory pools are set to non-zero values, then those values are used as minimum levels by Automatic Shared Memory Management. You would set minimum values if an application component needs a minimum amount of memory to function properly.

The following pools are manually sized components and are not affected by Automatic Shared Memory Management:

  • Log buffer

  • Other buffer caches, such as KEEP, RECYCLE, and other block sizes

  • Fixed SGA and other internal allocations

The memory allocated to these pools is deducted from the total available for SGA_TARGET when Automatic Shared Memory Management computes the values of the automatically tuned memory pools.

See Also: