Modernize Impala Support

The Support for the built-in Impala Connector is ancient. It is based on Impala 2.7 (according to the name of the adapter "cloudera_impala_2_7") which was the recent version in CDH 5.9 (see here: Cloudera Impala 2.7.0 New Features). CDH 5.9 itself was released back in October 2016 (see here: CDH 5.9 RelNotes) and thus is more than 6 years old by now.

Impala versions released in the meantime with significant improvements/changes (see here: Apache Impala New Features)

• 2.8 (CDH 5.10)

• 2.9 (CDH 5.12)

• 3.0.0 (CDH 6.0)

• 3.1.0 (CDH 6.1)

• 3.2.0 (CDH 6.2)

• 3.3.0

• 3.4.0 (CDP 7.1)

• 4.0.0

• 4.1.0

• 4.2.0

It would be highly appreciated if this adapter was updated (or a new one created) to support all the new features (from at least Impala 3.4.0) and integrate well with TDV.

Just to name a few:

• support CTEs

• support multiple distinct clauses in a single query

• support for integer division (either the function quotient(a, b) or the syntax "a DIV b" (see Impala Operators) or automatically rewrite "a / b" into "a DIV b" for pushdown)

• ...

And also the impala jdbc 4.2 driver for Java 8 should be used (unfortunately there's no jdbc 4.3 version for Java11 yet). The currently used driver "com.cloudera.impala.jdbc4.Driver" is the jdbc 4.0 one for Java 6 which is ancient aswell by now and also not maintained anymore. Alternatively let us specify the classname of the driver ourselves.

I know one can create a custom adapter inheriting from the system adapter to circumvent this, but all customers had to do this themselves, creating a lot of work. If TIBCO implemented this then it had to be done just once.