processing of messages in pub/sub is higher than expected but no error logged in stack driver what could be the underlying problem

Hi Priya, can you elaborate on what you mean by processing of messages is higher? Are you seeing higher numbers of messages being processed in general, or a higher number of messages pending or failing delivery?
Generally you wouldn’t see an error as such in Stackdriver from Pub/Sub, but a metric that would give an indication as to the underlying problem.