How to combine heuristic and explicit type mapping

[Bios-Marcel]

Hey

I've checked the docs and saw this: https://docs.eclipsestore.io/manual/storage/legacy-type-mapping/index.html#explicit-mapping

It claims you can combine the heuristic and the explicit type mapping. However, I couldn't find any examples.

Initially I thought it would automatically apply the heuristic mapping, even if you provide an explicit mapping. I am also not 100% sure I provided the explicit mapping the right way. This is what I did:

    foundation.onConnectionFoundation( connectionFoundation -> {
      connectionFoundation.setRefactoringMappingProvider(
          PersistenceRefactoringMappingProvider.New( List.of(
              KeyValue.New( "a", "b" )
          ) ) );
    } );

Upon starting with an older database, I get Caused by: org.eclipse.store.storage.exceptions.StorageException: TypeId not resolvable via type dictionary: 1000088, which I assume, means that the heuristic mapping wasn't applied at all.

The reason I am trying to do this, is that the algorithm seems to have match two completely unrelated fields, which caused a start failure.

It matched char grundueckstyp to String grundstueckBauherr. I've seen that the algorithm uses Levenshtein, so this feels like a bug, as the distance should be relatively big and the types don't even match.

[hg-ms]

We’re currently refactoring the documentation, maybe the next version will bit more readable, it is already in the project main branch: https://github.com/eclipse-store/store/blob/main/docs/modules/storage/pages/legacy-type-mapping/index.adoc

It should be sufficient to define an explicit mapping only for the elements that the heuristic can’t handle correctly:

KeyValue.New("org.example.MyClass#field1", " org.example.MyClass#field2")

Ensure that you use the full class name!

[Bios-Marcel]

Hm, i did provide full paths and no typos 🤔

Our concrete case is this btw:

Version 1: Has field x
Version 2: Deletes field x
Version 3: Adds y

When updating directly from 1 to 3, it matches x and y. The names are grundstueckstyp and grundstueckBauherr AND they have different types. Shouldn't this qualify as a bug, given the levenshtein distance should be relatively big?

Or is there a way to configure the required similarity factor?

[hg-ms]

Maybe you can check what the mapping decides by enabling logging, the related logger should be named
org.eclipse.serializer.persistence.types.LoggingLegacyTypeMappingResultor.

To explicitly specify a field as deleted with no mapping:
KeyValue.New("myClass#x",null)
To explicitly specify a field as new with no mapping:
KeyValue.New(null, "myClass#y")

[Bios-Marcel]

Ah, i did it!, didn't realize i had to call onConnectionFoundation it in the same chain as setConfiguration and createEmbeddedStorageManager ...