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> Parallel Hint, How is default different?
post Jul 20 2006, 09:51 AM
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Can somebody tell me the difference between the following parallel hint formats?

1. select /*+ PARALLEL*/ from emp;
2. select /*+ PARALLEL (t, default) from emp t;

I am seeing different results for each query.

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post Jul 20 2006, 02:50 PM
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Hi Jerry,

default value is two times the number of CPUs in your system


The danger is setting parallel at the database level with the ALTER TABLE command like this:

Alter table customer parallel degree 35;

The recommended approach for using Parallel query is to add a parallel hint to all SQL statements that perform a full-table scan and would benefit from parallel query.

select /*+ FULL(emp) PARALLEL(emp, 35) */

Here's an OTM discussion of parallel hints:


Hope this helps . . .

Donald K. Burleson
Oracle Press author
Author of Oracle Tuning: The Definitive Reference
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