TABLE QUEUE

Description

Appears in a parallel execution plan

Versions

This operation was introduced in Oracle 8.1.5

This operation is implemented in the following versions

8.1.5
8.1.6
8.1.7
9.0.1
9.2.0

This operation has not yet been observed in Oracle 10.2.

Example

This operation appears in the slave process of a parallel query. The execution plan is only generated if the query is executed, therefore it is not sufficient just to explain the query.

The execution plan can be observed in V$SQL_PLAN

This example was developed using Oracle 9.2.0.1 on Windows 2000

This example requires the following table definition

    CREATE TABLE t1 (c1 NUMBER);

The table must have at least one row

    INSERT INTO t1 VALUES (0);

The table does not need to be analysed

The statement

    SELECT /*+ PARALLEL (t1,4) */ c1,COUNT(*)
    FROM t1
    GROUP BY c1;

generates the following execution plan

    0     SELECT STATEMENT Optimizer=CHOOSE
    1   0   SORT (GROUP BY)
    2   1     SORT (GROUP BY) 
    3   2       TABLE ACCESS (FULL) OF 'T1'

Step 1 executes the following SQL statement using slave processes

    SELECT /*+ CIV_GB */ A1.C0,COUNT(SYS_OP_CSR(A1.C1,0))
    FROM :Q86000 A1
    GROUP BY A1.C0;

This generates the following execution plan

    0     SELECT STATEMENT Optimizer=CHOOSE
    1   0   SORT (GROUP BY)
    2   1     TABLE QUEUE :Q86000