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Parallel_max_server on the parallel implementation and parameters

Parallel_max_server on the parallel implementation and parameters

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parallel_max_server parameters will be restricted to the parallel execution, the current value of the parameter 5
SQL> show parameter parallel

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NAME TYPE VALUE
------------------------------------ ----------- --- ---------
parallel_max_servers integer 5

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Parallel test form time to 8
SQL> alter table tt parallel 8;

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Then run a query
SQL> select * from tt;
...

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In another window, query the view v $ px_session to check the number of parallel execution
select * from v $ px_session

sid serial # qcsid
10,610
18 29 10
23,310
22,310
21,310
20,310

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Can see that a total of six session, the other five session is derived from the SID 10. Parallel line that will only reach 5 degrees.

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Parallel_max_server now be revised to 8, the implementation of the above steps again, we can see a total of nine session, the other 8 are generated by the parallel query.

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The reason to do this test, mainly in the first work will be read parallel to the high degree, but did not confirm the value of parallel_max_servers a result, the value of degree higher than the parallel_max_servers, this degree does not work in practice. Should also improve the value of parallel_max_servers parallel in order to comply with the requirements.


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Tags: Change Parallel_max_server sid, sql, current value, parallel max, max server, server parameters, parallel execution, parallel implementation, parallel test, parallel query, parallel line, px, servers

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