Property | Description |
---|---|
Parameter type |
Integer |
Default value |
Operating system-dependent |
Modifiable |
No |
Range of values |
Minimum: 2148 Maximum: 65536, but some operating systems may have a smaller value |
Basic |
No |
Oracle RAC |
Multiple instances must have the same value. |
PARALLEL_EXECUTION_MESSAGE_SIZE
specifies the size of messages used for parallel execution (formerly referred to as parallel query, PDML, Parallel Recovery, replication).
On most platforms, the default value is as follows:
16384
bytes if COMPATIBLE
is set to 11.2.0
or higher
4096
bytes if COMPATIBLE
is less than 11.2.0
and PARALLEL_AUTOMATIC_TUNING
is set to true
2148
bytes if COMPATIBLE
is less than 11.2.0
and PARALLEL_AUTOMATIC_TUNING
is set to false
The default value is adequate for most applications. Larger values require a larger shared pool. Larger values result in better performance at the cost of higher memory use. For this reason, replication gets no benefit from increasing the size.
Note:
When PARALLEL_AUTOMATIC_TUNING
is set to TRUE
, message buffers are allocated out of the large pool. In this case, the default is generally higher. Note that the PARALLEL_AUTOMATIC_TUNING
parameter has been deprecated.
See Also:
Oracle Database VLDB and Partitioning Guide to learn how this parameter affects memory consumption for parallel operations, including parallel execution