BUFFER (SORT)
Description
Performs a memory sort on a row source
CREATE TABLE t1 (c01 NUMBER);
CREATE INDEX T1_C1 ON T1(C01);
CREATE TABLE t2 (c02 NUMBER);
BEGIN
DBMS_STATS.GATHER_TABLE_STATS(ownname => 'SCOTT',
tabname => 'T1',
estimate_percent => 30,
method_opt => 'for all columns size repeat',
no_invalidate => FALSE,
degree => 8,
cascade => TRUE);
END;
BEGIN
DBMS_STATS.GATHER_TABLE_STATS(ownname => 'SCOTT',
tabname => 'T2',
estimate_percent => 30,
method_opt => 'for all columns size repeat',
no_invalidate => FALSE,
degree => 8,
cascade => TRUE);
END;
SQL> set autot trace
SQL> SELECT t1.c01, t2.c02 FROM t1,t2;
Execution Plan
----------------------------------------------------------
Plan hash value: 787647388
-----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-----------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 26 | 4 (0)| 00:00:01 |
| 1 | MERGE JOIN CARTESIAN| | 1 | 26 | 4 (0)| 00:00:01 |
| 2 | TABLE ACCESS FULL | T1 | 1 | 13 | 2 (0)| 00:00:01 |
| 3 | BUFFER SORT | | 1 | 13 | 2 (0)| 00:00:01 |
| 4 | TABLE ACCESS FULL | T2 | 1 | 13 | 2 (0)| 00:00:01 |
-----------------------------------------------------------------------------
