enable_mv_binlog_minimal_mode

Description

enable_mv_binlog_minimal_mode specifies whether to enable the binlog minimal mode for incremental refresh 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 DML operations on materialized views. Other DML operations are not affected.

• 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 on 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 can improve the refresh performance of materialized views. However, it simplifies the content of CLOG. If downstream data synchronization links (such as CDC + OMS) rely on complete CLOG data 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 complete CLOG data of materialized views.

Examples

1. Enable the binlog minimal mode for incremental refresh 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. During incremental refresh, DML operations use the binlog minimal mode.

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

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

   obclient> ALTER SYSTEM SET enable_mv_binlog_minimal_mode = False;