Full ERROR Message Example

ERROR [RMI TCP Connection(51917)-127.0.0.1] 2020-04-26 01:58:57,640 StorageService.java:5204 - Caught an exception while draining
java.lang.AssertionError: null

What does this ERROR message mean?

The error is a generic catch-all to report a problem during the drain phase of a normal shutdown. Cassandra calls the drain procedure when the shutdown hook is invoked. It is responsible for stopping new compactions, flushing commitlogs, stopping client requests, hints and completing pending mutations.

Why does this ERROR occur?

It happens when Cassandra/DSE encounters an unexpected situation during the drain. There could be multiple explanations, and are usually related to I/O issues that cause problems with flushing data to disk. The accompanying stack trace should be analyzed to determine the cause.

How do you fix this ERROR?

The fix is dependent on why the drain failed. A complete stack trace and any earlier messages should be analysed to determine the root cause. Datastax technical support will be able to advise.