Alternating Least Squares (ALS) Model not supported (deploy_db)

[ZachC16]

ALS models (https://spark.apache.org/docs/latest/ml-collaborative-filtering.html) do not appear to be supported. There is an error when attempting to use deploy_db to deploy this type of model to a database.

To replicate: train an ALS Model, log it to mlflow, and then attempt to deploy it to a database with deploy_db.

Stack trace:

Py4JJavaError: An error occurred while calling o184.transform. : java.lang.NullPointerException at org.apache.spark.ml.recommendation.ALSModel.transform(ALS.scala:311) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244) at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357) at py4j.Gateway.invoke(Gateway.java:282) at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132) at py4j.commands.CallCommand.execute(CallCommand.java:79) at py4j.GatewayConnection.run(GatewayConnection.java:238) at java.lang.Thread.run(Thread.java:745)