In one of our site application is running with JAVA SDK(Version 2.x) while trying to connect Couchbase server(Version 5.5),
we are seeing below Exception in the application log file. We had attached the same for your reference.
java.lang.IllegalStateException: The content of this Observable (queryRow.c6086f0b-1f9f-408f-9d95-d33f29345a74) is already released.
Subscribe earlier or tune the CouchbaseEnvironment#autoreleaseAfter() setting.
Unfortunately we cannot help with the 2.x SDK series anymore, as it has been end-of-life since March 2022 (please see Enterprise Software Support Policy | Couchbase). Please upgrade to the 3.x series using the migration guide.
If it helps - the error indicates that the application has run a query but then not subscribed to the resulting Observable in time, and a timeout has occurred. You can either subscribe immediately (best option) or tune the CouchbaseEnvironment#autoreleaseAfter() parameter. If in your code you already are subscribing immediately, personally I would be checking for any evidence of things that could have caused massive application slowdown - large GC pauses, an overloaded application, that kind of thing.