PARALLEL hint

The PARALLEL hint causes the optimizer to break a query into pieces (the degree of parallelism) and process each piece with a different process. The PARALLEL hint will enable the use of parallel operations. If the degree is not specified with the hint, the default degree specifiedduring the table creation will be used.

Syntax:

select /*+ PARALLEL (table, DEGREE) */ ...

The degree is the number of pieces into which the query is broken.

Example1:

select /*+ PARALLEL (order_line_items) */ invoice_number, invoice_date

from order_line_items

order by invoice_date;

Example2:

select /*+ PARALLEL (order_line_items, 4) */ invoice_number, invoice_date

from order_line_items

order by invoice_date;

This statement does not specify a degree of parallelism. The default degree of parallelism is dictated by the table definition when the table was created.

Example3:

select /*+ PARALLEL (oli, 4) */ invoice_number, invoice_date

from order_line_items oli

order by invoice_date;