PX RECEIVE

Description

Parallel slave process - receive rows from child processes

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;

    CREATE TABLE t2
    (
      c1 NUMBER,
      c2 NUMBER
    )
    PARALLEL 2;

The statement

    SELECT t1.c2,t2.c2
    FROM t1,t2
    WHERE t1.c1 = t2.c1;

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         HASH JOIN
5   4           PX BLOCK ITERATOR 
6   5             TABLE ACCESS (FULL) OF 'T1'
7   4           BUFFER (SORT)
8   7             PX RECEIVE
9   8               PX SEND (BROADCAST)
10  9                 PX BLOCK ITERATOR
11 10                   TABLE ACCESS (FULL) OF 'T2'