Sync Gateway: issue starting DCP streams

[Marcus Folkeryd]

Hi!

I recently built the gateway from source (commit aa82177d3e65bec06887ecad6bb4cbf891042a08), hoping to utilize the new DCP feature. 

When testing this I noticed that new documents/revisions were not being shown in the changefeed (even when setting 'since' to 0/1). Restarting the gateway resolved the issue for all "dormant" changes so to speak, but any new changes suffered from the same issue. 

Looking at the log I saw this:

10:36:56.430152 WARNING: Feed%!(EXTRA string=Error processing DCP stream: %v, *errors.errorString=error: HandleRecv, err: bad rollback extras: &gomemcached.MCResponse{Opcode:0x53, Status:0x23, Opaque:0x377, Cas:0x0, Extras:[]uint8{}, Key:[]uint8{}, Body:[]uint8{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x4, 0xb8}, Fatal:false}) -- base.(*DCPReceiver).OnError() at dcp_feed.go:75

I'm running Couchbase 3.0.1 Enterprise Edition (build-1444).

Looking at https://github.com/couchbaselabs/dcp-documentation, 0x53 simply means the client wants to start a dcp stream, and the returned op code 0x23 indicates that the client should "rollback". 

Since I'm not familiar at all with how this works, maybe someone could shed a light on this issue?

Thanks in advance!

[Adam Fraser]

This sounds like a legitimate issue - can you file a ticket in the github repo?  Any details on your bucket configuration, and how new documents are being added to the bucket, would be helpful.

Thanks,
Adam

[Adam Fraser]

Found what looks like the root cause - fixing as https://github.com/couchbase/sync_gateway/issues/628

[Marcus Folkeryd]

I haven't had time to reproduce this issue, but I'll make sure to try it out again. Thanks a bunch!