Home » Oracle » 1z0-117 » What four changes could you make to help avoid the error and ensure that the query executes in parallel?
An application accessing your database got the following error in response to SQL query:
ORA-12827: insufficient parallel query slaves available
View the parallel parameters for your instance:
No hints are used and the session use default parallel settings.
What four changes could you make to help avoid the error and ensure that the query executes in parallel?
A. Set PARELLEL_DEGREE_POLICY to AUTO
B. Increase the value of PARELLEL_MAX_SERVERS.
C. Increase PARELLEL_SERVERS_TARGET.
D. Decrease PARELLEL_MIN_PERCENT.
E. Increase PARELLEL_MIN_SERVERS.
F. Decrease PARELLEL_MIN_TIME_THRESHOLD.
G. Increase PARELLEL__MIN_TIME_THRESHOLD.
Correct Answer: ACDG
Explanation/Reference:
C: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 AUTO, Oracle will queue SQL statements thatrequire 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_SERVER_TARGET.
By default, PARALLEL_SERVER_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.
D:
Note:ORA-12827:insufficient parallel query slaves available
Cause:PARALLEL_MIN_PERCENT parameter was specified and fewer than minimum slaves were acquired
Action:either re-execute query with lower PARALLEL_MIN_PERCENT or wait until some running queries are completed, thus freeing up slaves
A, G:PARALLEL_MIN_TIME_THRESHOLD specifies the minimum execution time a statement should have before the statement is considered for automatic degree of parallelism. By default, this is set to 30 seconds. Automatic degree of parallelism is only enabled if PARALLEL_DEGREE_POLICY is set to AUTO or LIMITED.
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