Hi David, Thank you for your reply.
Regarding NIFI-12468: whenever an Xodus transaction exceeds 60 seconds, the database connection is terminated, and NiFi does not recover without a restart. (Interestingly, with NiFi-1.x using Java11, recovery is not an issue.) I also evaluated YouTrackDB, but ultimately decided against it. As an object-oriented graph database, YouTrackDB seems to be a more high-level and complex solution than the simple key-value datastore we are looking for. Regards, Peter On Fri, Sep 19, 2025 at 3:19 PM David Handermann < [email protected]> wrote: > Hi Peter, > > Thanks for initiating this discussion. Despite activity on other > branches, I have also observed the lack of recent releases for Xodus. > I have not encountered the issues described in NIFI-12468, but I agree > that an alternative needs to be considered based on the lack of > maintenance activity. It is interesting that Xodus now mentions future > work on YouTrackDB, but that repository has not published a release to > Maven Central, so it does not appear to be in a helpful position. > > Anything that requires a native library and wrapper is not a great > candidate, like RocksDB as you noted. I looked at MapDB recently as > well, but I was also concerned about the maintenance level. I'm not > familiar with Chronicle-Map, so I plan to take a closer look. It > appears to have a number of dependencies, which is initially > concerning. Returning to H2 is not a good option, but mentioning it > for the sake of background. Apache Derby is another embedded database, > but it has had less maintenance in recent years. > > I plan to evaluate options and follow up, thanks again for raising the > topic! > > Regards, > David Handermann > > On Fri, Sep 19, 2025 at 7:46 AM Peter Gyori <[email protected]> wrote: > > > > Team, > > > > I am writing to propose we replace Xodus ( > > https://github.com/JetBrains/xodus ) in NiFi with a more actively > > maintained library. This change is necessary due to two key issues: > > > > - The Xodus project is no longer under active development. > > - We've encountered issues with Xodus when running NiFi on Java 21, as > > detailed in the comments of > > https://issues.apache.org/jira/browse/NIFI-12468 > > > > I have evaluated some potential replacements and have summarized my > initial > > findings below. > > > > Replacement Candidates: > > > > - RocksDB https://github.com/facebook/rocksdb > > - Pros: Popular, actively maintained, and license-compatible. > > - Con: Written in C++ and relies on JNI. > > - MapDB https://github.com/jankotek/mapdb > > - Pros: Java-based and license-compatible. > > - Con: The last release was in January 2024. > > - Chronicle-Map https://github.com/OpenHFT/Chronicle-Map > > - Pros: Java-based, actively maintained, and license-compatible. > > > > I welcome your input on this proposal, these candidates or any other > > alternatives you might suggest. > > > > Regards, > > Peter >
