Registry error "comparison method violates its general contract"

[tendrie]

When accessing a register, we got this error

Behind

However, there is no problem when accessing the content of the concerned register.

Deleting cannot be performed through LDregistry API, nor IHM. The solution will be to delete directly in Fuseki database. However there is the risk of compromising the integrity of our database. I could reproduce this issue on uploading data (a big file). So, I had to reset all the database to deal with it.

In my opinion, the safest solution will be to catch this exception. Or do you have some ideas to solve the problem without resetting the database?

thank you :)

[der]

Hmm. Never seen an error like that before and rather hard to work out what's going on, especially without the data.

However, it does look it might be a tricky bug in the underlying Apache Jena library: JENA-2333. If that is the cause then the full solution would be to port registry-core to jena 4.5.0 (or rather 4.7.0 which is the latest release). However, that would be a major undertaking since the transition from Jena 3.x to jena 4.x series involves some backward incompatible changes. Certainly not something we could attempt in the near future.

A possible thing to try would be to set the system property java.util.Arrays.useLegacyMergeSort to "true". That should force array sorting to use a merge sort algorithm instead of TimSort. If this is JENA-2333 then the order of listing the register might not be quite correct but at least it should avoid the exception.

Give that a try a let us know if that provides a work around.

[tendrie]

Thanks a lot for your solution.
It works fine. However I don't know if it can be permanent or not.