PARALLEL_MIN_PERCENT

PARALLEL_MIN_PERCENT lets you specify the minimum percentage of the requested number of parallel execution processes required for parallel execution. This parameter controls the behavior for parallel operations when parallel statement queuing is not enabled (when PARALLEL_DEGREE_POLICY is set to manual or limited). It ensures that an operation always gets a minimum percentage of parallel execution servers or errors out. 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 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.