SUMMARY
The following text is in the
sp_addsubscription section of SQL Server Books Online:
[@loopback_detection = ] 'loopback_detection'
Specifies if the Distribution Agent sends transactions that originated at the Subscriber back to the Subscriber. loopback_detection is nvarchar(5), and can be one of these values:
|
| true | Distribution Agent does not send transactions originated at the Subscriber back to the Subscriber. The value can be set to true only if the subscription update_mode is synctran and the article table has a published timestamp column |
| false | Distribution Agent sends transactions that originated at the Subscriber back to the Subscriber |
| NULL (default) | |
The preceding text implies that you can set the
@loopback_detection option to TRUE only if:
- The subscription is an Immediate Updating subscription (@update_mode= 'sync tran').
-and-
- A published timestamp column exists in the table.
However, that statement is not completely true. The following section provides you with more information about the correct usage of the
@loopback_detection option:
By default, subscription level loopback_detection is only set on for updateable subscriptions (immediate or queued). It is left as "false" for read-only subscribers. However, that does not mean that you cannot turn the option on for read-only subscriptions. The
@loopback_detection option is used for bi-directional replication. The
@loopback_detection option tells the Distribution Agent not to apply subscriber-originated commands back to the same subscriber.