Initialization parameters

streams_pool_size This parameter specifies, in bytes, the size of the Streams pool. The Streams pool contains captured events. The Streams pool is part of the System Global Area (SGA). In addition, the Streams pool is also used for internal communication during parallel capture and applies. By setting this parameter, a new pool of memory within the SGA called Streams pool is dedicated to the use of Streams buffers.

If the size of the Streams pool is greater than zero, any SGA memory used by Streams is allocated from the Streams pool. If the Streams pool size is set to zero, the SGA memory used by Streams is allocated from the shared pool and it may use up to 10% of the shared pool only. When Streams buffers are allocated from the shared pool, there will be a limitation on how much memory can be used.

This parameter can be modified; however, if it is set to zero when an instance starts, increasing it beyond zero has no effect on the current instance because it is already using the shared pool for Streams buffer allocations. If this parameter is set to a value greater than zero when an instance starts and is then reduced to zero when the instance is running, Streams processes and jobs will not run. Oracle recommends that the size of the Streams pool be adjusted for each of the following factors:

• 10 MB for each Capture process parallelism
   

• 1 MB for each Apply process parallelism
   

• 10 MB or more for each Queue staging captured events
   

• The DBA must ensure that enough buffers can be created. Failure to do so may cause memory contention.

timed_statistics This parameter specifies whether or not statistics related to time are collected. To collect elapsed time statistics in the dynamic performance views related to Streams, this parameter should be set to TRUE. The views that include elapsed time statistics include: