Traceability of failure is very difficult in N1ql transaction

Whenever there is a failure in N1ql transaction, Figuring out what exactly failed is very difficult. There are times the issue occurs only once, though there is cbcollect logs, most of the time it's not enough to figure out the issue.

Especially whenever there is "Document Not Found" issue, there is no data on for which document it failed. Most of the time, the documents which we are trying to delete always present in the cluster and yet we get "Document Not Found" error.

It's quite difficult to figure out the error is valid error or not. Especially when it comes to concurrency tests. It will be easier if we know at least for which document we are getting the error.