Performance issue with couchbase 6.1


I am new to couchbase and facing a performance issue with Couchbase 6.0. We have a couchbase server 6.0 installed as a single and a cluster of 3 nodes. When doing performance test we are getting concurrent timeout exception with single user when i am try to do a frequent get and update on the same object.

The error logs is as follows
java.util.concurrent.TimeoutException: {“b”:“demo_test”,“r”:“”,“s”:“n1ql”,“c”:“6BEDCBFD94723A8B/FFFFFFFFF7E58670”,“t”:7500000,“i”:“532e7ab6-6b6b-46d8-9182-922c463de996”,“l”:“”}

Any help on the above topic will be great.