Constant Error in the log - Exception in thread Thread[CompactionExecutor:3903,1,main] java.lang.NullPointerException: null
We are on Cassandra 3.7 and have a 8 node cluster , 2DC, with 4 nodes in each DC. RF=3 The below error message is being logged to the system.log exactly every Minute. ERROR [CompactionExecutor:5751] 2019-06-09 03:24:50,585 CassandraDaemon.java:217 - Exception in thread Thread[CompactionExecutor:5751,1,main] java.lang.NullPointerException: null ERROR [CompactionExecutor:5751] 2019-06-09 03:25:50,592 CassandraDaemon.java:217 - Exception in thread Thread[CompactionExecutor:5751,1,main] java.lang.NullPointerException: null ERROR [CompactionExecutor:5753] 2019-06-09 03:26:50,709 CassandraDaemon.java:217 - Exception in thread Thread[CompactionExecutor:5753,1,main] java.lang.NullPointerException: null ERROR [CompactionExecutor:5753] 2019-06-09 03:27:50,734 CassandraDaemon.java:217 - Exception in thread Thread[CompactionExecutor:5753,1,main] We have been seeing this error for some time now. But this error is showing only on 5 out of the 8 nodes. It does not provide any more details of the error even if we enable the Debug Mode. I am not sure what table that this error is related to either. We run repairs with -pr option every alternate day and they have been running successfully. nodetool compactionstats shows 0 pending tasks. pending tasks: 0 We are trying to figure out what this error indicates and if its a concern that we need to address. Any other suggestions also will be greatly appreciated.
