Skip Headers
Oracle® Database Reference
12c Release 1 (12.1)

Go to Documentation Home
Go to Book List
Book List
Go to Table of Contents
Go to Index
Go to Master Index
Master Index
Go to Feedback page
Contact Us

Go to previous page
Go to next page
PDF · Mobi · ePub


Property Description
Parameter type Integer
Default value PARALLEL_THREADS_PER_CPU * CPU_COUNT * concurrent_parallel_users * 2
Range of values 0 to PARALLEL_MAX_SERVERS
Basic No

PARALLEL_SERVERS_TARGET specifies the number of parallel server processes allowed to run parallel statements before statement queuing will be used. When the parameter PARALLEL_DEGREE_POLICY is set to ADAPTIVE or AUTO, Oracle will queue SQL statements that require parallel execution, if the necessary parallel server processes are not available. Statement queuing will begin once the number of parallel server processes active on the system is equal to or greater than PARALLEL_SERVERS_TARGET.


Consumer groups that have been marked with the PARALLEL_STMT_CRITICAL directive are allowed to bypass the parallel statement queue, and therefore may drive the total number of active parallel server processes beyond PARALLEL_SERVERS_TARGET.

By default, PARALLEL_SERVERS_TARGET is set lower than the maximum number of parallel server processes allowed on the system (PARALLEL_MAX_SERVERS) to ensure each parallel statement will get all of the parallel server resources required and to prevent overloading the system with parallel server processes.

The number of concurrent parallel users running at default degree of parallelism on an instance depends on the memory management setting. If automatic memory management is disabled (manual mode), then the number of concurrent parallel users is 1. If PGA automatic memory management is enabled, the number of concurrent parallel users is 2. If global memory management or SGA memory target is used in addition to PGA automatic memory management, then the number of concurrent parallel users is 4.

Note that all serial (non-parallel) statements will execute immediately even if statement queuing has been activated.

See Also:

Oracle Database VLDB and Partitioning Guide for more information about this parameter