[NIFI-4775] Create a FlowFile repo backed by RocksDB

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.10.0
• Component/s: Core Framework
• Assignee: Brandon Rhys DeVries
• Reporter: Mark Payne
• Created: 12/Jan/18 20:15
• Updated: 15/Aug/19 15:46
• Resolved: 15/Aug/19 15:35

Description

Currently, when a FlowFile is written to the FlowFile Repository, the repo can either fsync or not, depending on nifi.properties. We should allow a third option, of fsync only for CREATE events. In this case, if we receive new data from a source we can fsync the update to the FlowFile Repository before ACK'ing the data from the source. This allows us to guarantee data persistence without the overhead of an fsync for every FlowFile Repository update.

It may make sense, though, to be a bit more selective about when do this. For example if the source is a system that does not allow us to acknowledge the receipt of data, such as a ListenUDP processor, this doesn't really buy us much. In such a case, we could be smart about avoiding the high cost of an fsync. However, for something like GetSFTP where we have to remove the file in order to 'acknowledge receipt' we can ensure that we wait for the fsync before proceeding.

NOTE: This functionality was ultimately provided in a new implementation backed by RocksDB

 

Issue Links

• relates to: NIFI-6416 WriteAheadFlowFileRepository.swapFlowFilesIn() not removing swapLocationSuffixes
• links to: GitHub Pull Request #2416
• links to: GitHub Pull Request #3638
• links to: GitHub Pull Request #3648