UI Document Editor "offset" issue

The content of this article applies to Couchbase Server 7.X and above.

Issue Summary:

The issue revolves around the offset (a.k.a. skip) limit in the Couchbase UI Document Editor. At the end of the article, you will understand more on the effects of the issue and the steps involved in resolving the issue.

Issue Indication:

The Couchbase UI Document Editor page permits users to see a batch of documents.

The size of the batch defaults to 10, but the user can set the size up to 200.

The UI also allows the user to set an offset (a.k.a. skip) value for the first document in the batch. This value is used to page through batches of documents (as highlighted in red):

In Couchbase Server v7.x and above, the UI does not enforce any limit on the value of offset. 

So when the user opens up the Couchbase UI Document Editor page with default limit=10 and skip=0. There are forward/backward arrows that show a new batch of documents by incrementing the value of offset with the current limit. The user can manually change the value of limit up to 200 but no larger. There is no restriction in the UI on values ofoffset, so the user can input a high offsetvalue into the text field on the screen and the UI will retrieve documents in that range. 

This high offsetvalue potentially leads to the connection between the Cluster Manager and Data Service to disconnect.

Because of this disconnect, Cluster Manager will report the node as warmup in Couchbase UI, but Data Service (i.e "memcached" process) will be up and running during this time. All the operations from the application/SDK will directly communicate with "memcached" process. Hence, this issue alone will not cause any downtime for application operations.

Issue Resolution:

To address this issue, the resolution involves restricting the offset limit in the Couchbase UI to a value less than or equal to 1000. This fix will be incorporated in Couchbase Server version 7.2.5 and subsequent releases.

In the interim, Couchbase Support advises users against configuring offset values exceeding 1000.