After you complete significant maintenance to the consolidated database   For example, you make changes to the consolidated database, which updates every row in the database. By default, SQL Remote creates and sends update messages to each subscribed remote. These update messages could include the UPDATE, DELETE, and INSERT statements for each row.

If you chose to synchronize the subscription using a SYNCHRONIZE SUBSCRIPTION statement, you only send the statements required to delete all the rows in the subscribed tables and the INSERT statements to insert all new rows.

When a remote database is out-of-step with the consolidated database   If a remote database becomes out-of-step with the consolidated database, you can try to use passthrough mode.

If using passthrough mode doesn't work, you can synchronize the subscriptions. When you synchronize subscriptions, you force the remote database into step with the consolidated database. A SYNCHRONIZE SUBSCRIPTION statement includes statements to delete the contents of the subscribed tables in the remote database and statements to insert the rows of the subscription from the consolidated database to the remote database.