do_sync_flag explains various status of synchronization between Source and Database and helps in Database to Source Replication.

do_sync_flag helps in updating existing data and inserting new data in Salesforce. (This is not applicable in case of Cassandra DB). The value of do_sync_flag & the description is shown in the below table.

• When Salesforce to Database replication is successfully completed, do_sync_flag for all the records in the database will be ‘Y’.

• If the data is edited / updated in database, it is required to edit / update the same in Salesforce too. To do this do_sync_flag value must be changed to ‘S’ along with the necessary changes to the records in database. After the replication (DB to Source) all these changes will reflect in Salesforce. 
  Example: Account sForce in Salesforce does not have Type which is already replicated in database. If the type is updated as ‘Customer – Channel’ in database, Salesforce must also be updated with the same. In order to update in Salesforce do_sync_flag value must be changed to ‘S’ and this must be saved before running the replication DB to Source. After successful run, Account sForce will have Type ‘Customer - Channel’.
  
  
  1. Account sForce does not have Type in Salesforce.
     
  2. After replication (SF to DB), do_sync_flag value for sForce Account is ‘Y’ and sfType is ‘NULL’.
     
     
     
  3. sfType for sForce is manually updated as ‘Customer – Channel’ in database and then do_sync_flag is manually updated as ‘S’.
     
     
     
  4. After running Replication (DB to Source), sForce Account in Salesforce is updated with the Type ‘Customer – Channel’.
     
     

• If the data is deleted in Salesforce after replication (Source to DB), when the replication (Source to DB) is run for the next time, do_sync_flag value changes to ‘D’. 
  Example: Account ‘Pyramid Construction Inc.’ is deleted in Salesforce which is already replicated in database.  Account Pyramid Construction Inc. data is already available in database with do_sync_flag value ‘Y’. When the Source to DB replication is done for the next time, do_sync_flag value changes to ‘D’ by itself. This signifies that Account ‘Pyramid Construction Inc.’ does not exist in Salesforce.
  
  
  1. After Replication (Source to DB), do_sync_flag value is ‘Y’ for the account ‘Pyramid Construction Inc.’
     
     
     
  2. Account ‘Pyramid Construction Inc.’ is deleted in Salesforce. 
     
     
     
  3. After Replication (Source to DB), do_sync_flag value changes to ‘D’.