We are experiencing an issue where content claims are not being cleaned up. This causes the content repo to grow, and eventually fill the disk. We only see this behavior when using the RocksDBFlowFileRepository, but not when using the WriteAheadFlowFileRepository.
Unfortunately, we have not been able to create a consistently reproducible test case to recreate the problem. It is only observed on a cluster that is heavily loaded. Evidence of the problem (besides the content repo filling up) is that upon restarting NiFi, there are hundreds of messages: 2021-09-22 11:39:50,052 INFO [main] 0.a.n.c.repository.FileSystemRepository Found unknown file /content_repository/60/1632307980953-60 (814776 bytes) in File System Repository; removing file The crux of the problem is that the claimant count for a given claim is not being updated correctly. The count never reaches zero even when all flowfiles which had been in the given claim have been dropped from NiFi. (This is why the claim is able to be removed on restart.) Therefore, the claim is considered "in use" and is not cleaned up. (Content archiving is disabled as well, so no claims are advanced to the archive.) The issue is not seen in 1.11.4, but is seen in 1.12.1 and 1.14.0. I suspect it may be related to changes made in NIFI-6849. https://issues.apache.org/jira/browse/NIFI-6849 Any insights or suggestions are greatly appreciated. Thanks! -Mark
