Oracle - Explain how to invoke Parallel Query posted by
Babu Kunwar
Explain how to invoke Parallel Query
In order to invoke Parallel Query the first thing we need to do is leave
sql_trace true in init.ora. In Parallel Query the most important tool is
sql_trace facility and v$pq_tqstat. Invoking parallel query example:
select * from COMPANY;
Invoke Degree of Parallelism (DOP) = 3
alter table COMPANY
parallel (degree 3); OR
select /*+ PARALLEL (company, 3) */ *
from COMPANY;
Where
• DOP = no. of parallel server processes associated with a single operation
• DOP specified at statement level, table/ index level or by default based on
the # of disks / CPUs
• Actual parallelism depends on free resources.
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