ALTER SESSION SET optimizer_dynamic_sampling : Session Variables « SQL PLUS Session Environment « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. SQL PLUS Session Environment
3. Session Variables

SQL>
SQL> ALTER SESSION SET optimizer_dynamic_sampling = 0;

Session altered.

SQL>
SQL>
SQL> CREATE TABLE myTable AS SELECT * FROM all_objects;

Table created.

SQL>
SQL>
SQL> CREATE TABLE myTable2 AS SELECT object_id, object_name FROM myTable;

Table created.

SQL>
SQL> ALTER TABLE myTable2 ADD object_application VARCHAR2(12);

Table altered.

SQL>
SQL> UPDATE myTable2 SET object_application = 'WORKSHOP';

12597 rows updated.

SQL>
SQL> COMMIT;

Commit complete.

SQL>
SQL> SET AUTOTRACE TRACEONLY EXPLAIN;
SQL>
SQL>
SQL> ALTER SESSION SET optimizer_dynamic_sampling = 1;

Session altered.

SQL>
SQL>
SQL> SET AUTOTRACE OFF;
SQL>
SQL> DROP TABLE myTable2;

Table dropped.

SQL>
SQL> DROP TABLE myTable;

Table dropped.

SQL>