Questionlink
Can I reduce my MAR usage by using column blocking?
Answerlink
No, you can’t reduce your MAR usage with column blocking. MAR is the number of distinct primary keys synced from the source system to your destination in a given calendar month.
If you update (rename) a blocked column that is not a primary key column in your source table, the update counts towards your MAR usage.
NOTE: You can’t block primary key columns.
Causelink
Column blocking allows you to exclude columns containing sensitive data from your syncs.