Example ERROR message

CompactionManager.java:xxx - Failed to submit background task

What does this ERROR message mean?

An attempt to submit a compaction or validation task failed

Why does this ERROR occur?

Most failures to submit a task are the result of the executor being shutdown (eg due to the node being drained) and result in a message such as:

CompactionManager.java:1903 - Executor has been shut down, not submitting background task

However, if the executor has not been shutdown and an attempt to submit the task fails with RejectedExecutionException then the "Failed to submit" message will be seen. There may be a number of potential causes such as for example the scheduler queues being full.

How do you fix this ERROR?

Occurrences of this error message are rare and require investigation of the RejectedExecutionException  details and the node state to determine the root cause. Please contact Datastax Support.