CALCITE-3533 - Map non-jdbc data types to ANY in JdbcSchema

[jeremyosterhoudt]

This PR allows non-standards JDBC/SQL types to be processed as ANY. Databases such as Oracle and SQLServer (among others) often support SQL types that are not defined as part of the standard Java JDBC type mapping.

Currently Avatica (and by proxy Calcite) throw an exception when these types are encountered. However, for many non-standard types this prevents the query from executing successfully even though the results are retrieved and displayed correctly when ANY is used for these scenarios (SQLSever's DataTimeOffset for example).

While this is not a fix per se I do believe this is an improvement over the current behavior. Types could be added directly, however, some types like Oracle's DateTime With Offset require the Oracle JDBC driver to convert. This would mean including the JDBC driver in Avatica with is likely undesirable. Ideally I think a nice enhancement would be to allow developers/users to specify a non-standard type conversion class/factory that could be called when these types are encountered while embedding any needed libraries (I'm hoping to have a conversation around this and partake in the implementation).

[mihaibudiu]

The PR title does not match the issue title.
Also, I find the title confusing: returned by whom?
Maybe you can update the JIRA issue to explain what this achieves.
Is there a test to show what new capabilities this offers?

[jeremyosterhoudt]

I updated the title and added some tests to cover the functionality.

I don't yet have access to Jira to update the issue (I filled out the info and the access is pending). However, the Jira ticket currently does explain what this change is intended to cover. Mapping SqlType.ANY for types not present in the Types Enum. The current implementation makes connecting to tables for some database impossible that contain types not in the Types Enum (Oracle and SQL Server specifically, but others as well). I detailed in the main body of the PR why some of these types can't/shouldn't be added to Avatica directly.

[mihaibudiu]

These unit tests are not particularly illuminating.
I see that avatica has a dependency on HSQLDB, is there a test you can write using this database that tests the new capability end-to-end?

[rubenada]

@jeremyosterhoudt would it be possible to fix the check-style of the PR, and also have some end-to-end test showing the fix (as suggested by @mihaibudiu ) ?

[zabetak]

It seems that the easier way to showcase the problem (IllegalArgumentException) in a more realistic setting would be through Calcite. @jeremyosterhoudt In addition to the PR here can you come up with a PR in the calcite code base that adds relevant test(s) (possibly in https://github.com/apache/calcite/blob/main/core/src/test/java/org/apache/calcite/test/JdbcTest.java).

In some cases a failure/crash is preferred, compared to returning wrong results or causing data corruption so we should ensure that the fix here will not cause some other undesired side effects.