[jira] [Created] (CALCITE-3394) Can not register implementation of a UDF with RexImpTable and use the same with RelBuilder

[Vaishnavee Kulkarni (Jira)]

Vaishnavee Kulkarni created CALCITE-3394:
--------------------------------------------

             Summary: Can not register implementation of a UDF with RexImpTable 
and use the same with RelBuilder
                 Key: CALCITE-3394
                 URL: https://issues.apache.org/jira/browse/CALCITE-3394
             Project: Calcite
          Issue Type: Bug
          Components: core
    Affects Versions: 1.21.0
            Reporter: Vaishnavee Kulkarni


I am trying to register a simple UDF that returns the length of input string. I 
can do this with prepareStatement approach -
{code:java}
public static class MyUdf1 {
   public Integer eval(String a) {
      return a.length();
   }
}

public void testUDF() {
final String strLenSql = "select STRLEN('SampleString') from emp";
ScalarFunction strLenFunction = ScalarFunctionImpl.create(MyUdf1.class, "eval");
calciteConnection.getRootSchema().add("STRLEN", strLenFunction);

ResultSet resultSet = 
calciteConnection.prepareStatement(strLenSql).executeQuery();
resultSet.next();
System.out.println(resultSet.getString(1));
}

{code}
 

When I try the similar steps with _RelBuilder_, I can successfully register the 
_SqlOperator_; but am unable to refer to the implementation of this operator. 
The builder refers to _RexImpTable_'s maps for the function table 
implementation and there is no public/protected api exposed for these maps. 
{code:java}
SqlFunction length = new SqlFunction("STRLEN",
      SqlKind.OTHER_FUNCTION,
      ReturnTypes.INTEGER,
      null,
      OperandTypes.STRING,
      SqlFunctionCategory.USER_DEFINED_FUNCTION);

SqlStdOperatorTable sqlStdOperatorTable = SqlStdOperatorTable.instance();
sqlStdOperatorTable.register(length);

FrameworkConfig frameworkConfig = Frameworks.newConfigBuilder()
      .parserConfig(SqlParser.Config.DEFAULT)
      .defaultSchema(connection.getRootSchema().getSubSchema("SYSTEM"))
      .programs(Programs.sequence(Programs.ofRules(Programs.RULE_SET), 
Programs.CALC_PROGRAM))
      .operatorTable(sqlStdOperatorTable)
      .build();

final RelBuilder builder = RelBuilder.create(frameworkConfig);
RelNode udfRelNode = builder
      .scan("EMP")
      .project(builder.call(length,builder.literal("SampleString")))
      .build();

ResultSet resultSet = RelRunners.run(udfRelNode).executeQuery();
{code}
 

This code throws exception - 


{code:java}
Caused by: java.lang.RuntimeException: cannot translate call STRLEN($t3)Caused 
by: java.lang.RuntimeException: cannot translate call STRLEN($t3) at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translateCall(RexToLixTranslator.java:756)
 at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translate0(RexToLixTranslator.java:730)
 at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translate(RexToLixTranslator.java:199)
 at 
org.apache.calcite.adapter.enumerable.RexToLixTranslator.translate0(RexToLixTranslator.java:684)
{code}
There are no junits that show this working with _RelBuilder_. Is it possible 
currently to register and use the udfs with RelBuilder?



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