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Filter DMLs Using SQL Expressions |
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In the process of incremental data migration, you can filter certain types of binlog events using the Filter Binlog Events feature. For example, for archiving or auditing purposes, you can filter out DELETE events when migrating data to the downstream. However, Binlog Event Filter cannot judge with a greater granularity on whether to filter out a specific row of DELETE events.
To solve the above issue, DM supports filtering data during incremental migration using binlog value filter since v2.0.5. The binlog in the ROW format supported by DM has the values of all columns in binlog events. You can configure SQL expressions according to these values. If the SQL expressions evaluate a row change as TRUE, DM will not migrate the row change downstream.
For detailed operation and implementation, see Filter DML Events Using SQL Expressions.