I like the idea of an adapter-supplied function, but it’s not in Calcite right now.
The easiest thing is probably to define the function in the JSON model [1]. That should get you through validation (which is where you’re tripping up right now). Then you’ll need to push the function down to the storage engine. There isn’t a nice way of declaring what UDFs a particular engine can handle. I fear that you’ll need to modify the Solr rules. Julian [1] https://calcite.apache.org/docs/model.html#function <https://calcite.apache.org/docs/model.html#function> > On Mar 27, 2017, at 11:23 AM, Timothy Potter <thelabd...@gmail.com> wrote: > > I'm trying to add the ability to push-down the evaluation of a > function to my storage engine (Solr in this case). For instance, > > select movie_id, user_id, custom_rating('foo') as rating from movie_ratings > > where custom_rating('foo') is some function in my storage engine. > > This seems like a UDF in Calcite terms but I'm not having any luck > getting the function node passed to my adapter code. > > I've tried adding a ScalarFunction to my schema but it gets evaluated > early (long before my adapter code gets hit). > > I've also tried a TableFunction, but always end up with this error (using > 1.11) > > Caused by: org.apache.calcite.runtime.CalciteContextException: From > line 1, column 27 to line 1, column 36: No match found for function > signature custom_rating(<CHARACTER>) > at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) > at > sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) > at > sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) > at java.lang.reflect.Constructor.newInstance(Constructor.java:423) > at > org.apache.calcite.runtime.Resources$ExInstWithCause.ex(Resources.java:463) > at org.apache.calcite.sql.SqlUtil.newContextException(SqlUtil.java:796) > at org.apache.calcite.sql.SqlUtil.newContextException(SqlUtil.java:784) > at > org.apache.calcite.sql.validate.SqlValidatorImpl.newValidationError(SqlValidatorImpl.java:4080) > at > org.apache.calcite.sql.validate.SqlValidatorImpl.handleUnresolvedFunction(SqlValidatorImpl.java:1614) > at org.apache.calcite.sql.SqlFunction.deriveType(SqlFunction.java:278) > at org.apache.calcite.sql.SqlFunction.deriveType(SqlFunction.java:223) > at > org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:4445) > at > org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:4432) > at org.apache.calcite.sql.SqlCall.accept(SqlCall.java:137) > > > which when debugging looks like the function isn't registered > correctly in the schema but I've overridden protected Multimap<String, > Function> getFunctionMultimap() in my schema impl. to include my > function. > > I scanned the docs and the UDF code (e.g. Smalls) but don't see an > example of a adapter supplied function. Any guidance you can provide > is appreciated. > > Thanks. > Tim
