Oracle® Database Reference 11g Release 2 (11.2) Part Number E25513-03 |
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PDF · Mobi · ePub |
Property | Description |
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Parameter type | Integer |
Default value | 0 |
Modifiable | ALTER SESSION |
Range of values | 0 to 100 |
Oracle RAC | Multiple instances can have different values. |
PARALLEL_MIN_PERCENT
lets you specify the minimum percentage of the requested number of parallel execution processes required for parallel execution. Setting this parameter ensures that parallel operations will not execute unless adequate resources are available. The default value of 0
means that no minimum percentage of processes has been set.
Consider the following settings:
PARALLEL_MIN_PERCENT = 50 PARALLEL_MIN_SERVERS = 5 PARALLEL_MAX_SERVERS = 10
If 8 of the 10 parallel execution processes are busy, only 2 processes are available. If you then request a query with a degree of parallelism of 8, the minimum 50% will not be met.
You can use this parameter in conjunction with PARALLEL_ADAPTIVE_MULTI_USER
. In a multi-user environment, an individual user or application can set PARALLEL_MIN_PERCENT
to a minimum value until sufficient resources are available on the system and an acceptable degree of parallelism is returned.
See Also:
Oracle Database Performance Tuning Guide for more information on tuning parallel execution
"PARALLEL_MAX_SERVERS", "PARALLEL_MIN_SERVERS", and "PARALLEL_ADAPTIVE_MULTI_USER"