Geodatabase Synchronization Hangs

[ChristopherMilack1]

I already posed this to the Server group but hoping I have more luck here - sorry for the crosspost!

I'm running into a seemingly random issue with ArcGIS Server 10.3 where the synchronization process hangs without error.  I have an iOS client (using the Esri SDK) and I'm using per-layer synchronization.

The majority of the time, synchronization succeeds but occasionally, it gets into a state where it never finishes.  I've kicked up server logging to DEBUG level and what I'm seeing is that at seemingly random times, the log messages for the sync process just stop. This often occurs when you wait a few days between syncs but we've also seen it happen immediately after generating and downloading a new replica. We've seen it occur at various times during layer processing for a number of different data sets. Once it happens, the replica will never sync and we have to wipe it out and generate a new one.

For example, I started a sync today and this was the last message in the log for the process:

Copying row with GlobalId: {F250C221-8896-4669-B60B-B58CBA4F0EB0} for dataset: T_58_Inserts. Dataset: T_58_Inserts. Replica: SDO.Ags_Fs_1464975077233.

At other times, it will hang and the last message will be mention acquiring an archive cursor like so:

Acquiring Archive Difference Cursor for dataset:...

I watched the server process in windows task manager and at the point when synchronization hangs, the process hits 6% CPU usage and stays there indefinitely. I've run SQL Server Profiler and don't see any obvious errors or hung queries.

My first thought is that the sync process has gotten into an infinite loop somehow - just a guess based on the CPU spike and the fact that there aren't clear database issues. 

Has anyone run into this? Any known issues?

Thanks!

[RexRobichaux2]

Hi Christopher,

    You mentioned trying to synch from an iOS client- so I just wanted to confirm if this is a mobile device you are attempting to synch from? If so there was a known bug BUG-000091460 that has been rectified with the ArcGIS 10.3.1 Feature Service Sync Performance Patch available here: ArcGIS 10.3.1 for (Desktop, Engine, Server) Feature Service Sync Performance Patch The aforementioned bug was known to cause inconsistent failure upon synchronization sometimes with the error:

• "Failed to acquire archive difference cursor".

Which seems to be where you are getting hung up. The above patch (if not currently installed) might be a worth a shot. Hope this helps!

[ChristopherMilack1]

Thanks for the tip. We installed that patch a while back and it got us past that issue a number of times.

I think we sorted out the problem we were having. It's been a few days now and no issues. We ended up having to wrap one of our definition expressions in parentheses. If we didn't, the query that was built to find the diffs on the server side was returning an invalid result set.

[RexRobichaux2]

Glad to hear you were able to resolve the issue Christopher- take care!

[JoshuaBixby]

In terms of cross posting, or not cross posting, a question created in one place can be "shared" to another place, which effectively eliminates the need to cross post.

[ChristopherMilack1]

Thanks. Noted for next time.