PX SEND (QC (RANDOM))

Description

Parallel execution - send random rows to queue coordinator process

Versions

This operation is implemented in the following versions

Example

This example was developed using Oracle 10.2.0.1 on Linux

This example requires the following table definitions

    CREATE TABLE t1
    (
      c1 NUMBER,
      c2 NUMBER
    )
    PARALLEL 2;

The statement

    SELECT COUNT(*) FROM t1;

generates the following execution plan

0     SELECT STATEMENT Optimizer=CHOOSE
1   0   SORT (AGGREGATE)
2   1     PX COORDINATOR
3   2       PX SEND (QC (RANDOM))
4   3         SORT (AGGREGATE)
5   4           PX BLOCK ITERATOR 
6   5             TABLE ACCESS (FULL) OF 'T1'