Automate the un-registering of replica

Question

I'm working on an arcpy script that removes a feature class and then recreates it. The feature class is part of a replica, and I need to recreate the replica as part of the script, however you cannot unregister a replica using arcpy.

If I manually remove the replica using Distributed Geodatabase > Manage Replicas > Unregister, the script works fine recreating the feature class and the replica, however if I don't manually remove it first the script fails:

Message: ERROR 000775: Replica with the same name already exists. 
Failed to execute (CreateReplica).

I have found my replica in SQL using:

SELECT *
FROM [GDB_ITEMS]
WHERE Type = '4ED4A58E-621F-4043-95ED-850FBA45FCBC'
AND Name = 'MyReplicaName'

Can I "safely" remove this entry in GDB_ITEMS to unregister my replica? If so, I could probably use arcpy to send the SQL to remove it just so I can continue with my script.

By "safely" I mean it's just a single reference and I don't need to remove it from 10 other tables as well to unregister the replica.

If it's relevant, the replica is two-way full SDE to SDE database replica.

Answer 1

Too bad you aren't using creating replicas from a feature service, then you could just use the REST API to unregister (pretty easy call with Python). I don't have an arcpy solution for you as I don't think it is available there yet.

I do have a Python comtypes ArcObjects solution that works though. I am using a modified version of the Snippets module. The first step is to get a pointer to an IWorkspace object, in my case a SQL Server SDE connection. The following code worked for me:

from arcobjects import *
import comtypes.gen.esriGeoDatabase as esriGeoDatabase  

def unregisterReplica(ws, replicaName=None, replicaID=None, replicaGUID=None):
    """Unregisters a replica from a database

    Required:
        ws -- Pointer to IWorkspace Interface
    Optional (need to use one of these):
        replicaName -- name of replica to unregister
        replicaID -- id of replica
        replicaGUID -- Guid of replica
    """
    wsReplicasAdmin = CType(ws, esriGeoDatabase.IWorkspaceReplicasAdmin2)
    wsReps = CType(ws, esriGeoDatabase.IWorkspaceReplicas)
    replica = None
    if replicaName:
        replica = wsReps.ReplicaByName(replicaName)
    elif replicaID:
        replica = wsReps.ReplicaByID(replicaID)
    elif replicaGUID:
        replica = wsReps.ReplicaByGuid(replicaGUID)

    if isinstance(replica, esriGeoDatabase.IReplica):
        rep_name = replica.Name
        wsReplicasAdmin.UnregisterReplica(replica, True)
        print 'Successfully unregistered: "{}"'.format(rep_name)

if __name__ == '__main__':

    instance = 'sde:sqlserver:ArcSQL'
    ws = Standalone_OpenSDE('SQLServer', instance, database='BMI_PhotoApp')
    name = 'DBO.test_1438722629060'

    reps = unregisterReplica(ws, name)

Please note that you can get at a replica by more than just its name. You can also get a replica by ID/Guid. Have a look at the IWorkspaceReplicas Interface. I have also added this function to my GitHub repo mentioned above.

Also the How do I access ArcObjects from Python post may help you figure out how to set everything up. You need to make sure you compile the .olb files for comtypes first.