enable_mv_binlog_minimal_mode

Description

enable_mv_binlog_minimal_mode specifies whether to enable the binlog minimal mode for incremental refreshes of materialized views.

Privilege requirements

• Query the parameter

  The sys tenant and all user tenants can query the value of this parameter by using the SHOW PARAMETERS statement or the GV$OB_PARAMETERS view.

• Modify the parameter

  The sys tenant and user tenants can modify this parameter.

Attributes

Considerations

• The enable_mv_binlog_minimal_mode parameter affects only the DML operations of materialized views. It does not affect other DML operations.

• The enable_mv_binlog_minimal_mode parameter is independent of the binlog_row_image parameter. It specifies the behavior of materialized views only.

  • If you enable the enable_mv_binlog_minimal_mode parameter, the DML operations of materialized views use the binlog minimal mode, regardless of the value of the binlog_row_image parameter.

• Enabling the enable_mv_binlog_minimal_mode parameter improves the refresh performance of materialized views. However, it simplifies the contents of CLOG. If downstream data synchronization links (such as CDC + OMS) rely on the complete CLOG of materialized views for migration and synchronization, enabling this parameter may cause exceptions in the synchronization links. Therefore, we recommend that you do not enable this parameter if downstream data synchronization links require the complete CLOG of materialized views.

Examples

1. Enable the binlog minimal mode for incremental refreshes of materialized views.

   obclient> ALTER SYSTEM SET enable_mv_binlog_minimal_mode = True;
   

2. Create a table named test_tbl1.

   obclient> CREATE TABLE test_tbl1(col1 INT, col2 INT, col3 INT);
   

3. Create a materialized view named mv1_t1.

   obclient> CREATE MATERIALIZED VIEW mv1_t1
       REFRESH FAST
       AS SELECT col2, COUNT(*) cnt
          FROM test_tbl1
          GROUP BY col2;
   

4. When you perform incremental refreshes, the DML operations use the binlog minimal mode.

   obclient> CALL DBMS_MVIEW.REFRESH('mv1_t1', 'f');
   

5. Disable the binlog minimal mode for incremental refreshes of materialized views.

   obclient> ALTER SYSTEM SET enable_mv_binlog_minimal_mode = False;