Init parameterOptimizer & SQL

PARALLEL_DEGREE_POLICY

What it controls

Whether Oracle chooses the degree of parallelism itself.

Know this before you change it

AUTO also turns on statement queuing and in-memory parallel execution. Try LIMITED first.

Default: MANUAL

Check and change it

1-- Current value on every instance2SELECT inst_id, name, value, isdefault, ismodified3FROM gv$parameter4WHERE name = 'parallel_degree_policy';5 6-- Value stored in the spfile7SELECT sid, value FROM v$spparameter WHERE name = 'parallel_degree_policy' AND isspecified = 'TRUE';8 9-- Dynamic: takes effect now and is kept after a restart10ALTER SYSTEM SET parallel_degree_policy = MANUAL SCOPE = BOTH SID = '*';11 12-- Or for your own session only13ALTER SESSION SET parallel_degree_policy = MANUAL;14 15-- Remove it from the spfile to go back to the default at the next restart16ALTER SYSTEM RESET parallel_degree_policy SCOPE = SPFILE SID = '*';

Open in the parameter referenceOracle's reference

More in Optimizer & SQL

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• OPTIMIZER_ADAPTIVE_STATISTICSAdaptive statistics features such as SQL plan directives and dynamic statistics (12.2 and later).
• OPTIMIZER_ADAPTIVE_PLANSLets the optimizer switch join methods during the first execution (12.2 and later).
• CURSOR_SHARINGWhether Oracle replaces literals with bind variables before parsing.
• STATISTICS_LEVELHow much performance data Oracle collects.
• OPTIMIZER_MODEWhether the optimizer aims for total throughput or fast first rows.
• DB_FILE_MULTIBLOCK_READ_COUNTBlocks read in one I/O during full scans.
• PARALLEL_MAX_SERVERSThe most parallel execution processes per instance.
• RESULT_CACHE_MAX_SIZEMemory for the server result cache.