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https://issues.apache.org/jira/browse/CALCITE-2966?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16814400#comment-16814400
]
Julian Feinauer commented on CALCITE-2966:
------------------------------------------
Hey [~danny0405] it seems that there was indeed a Bug in Calcite in the
RexImpTable.implementNullSemantics, there was Lines 1029ff
{code:java}
case FALSE:
// v0 != null && v1 != null && f(v0, v1)
for (Ord<RexNode> operand : Ord.zip(call.getOperands())) {
if (translator.isNullable(operand.e)) {
list.add(
translator.translate(
operand.e, NullAs.IS_NOT_NULL));
translator = translator.setNullable(operand.e, false);
}
}
list.add(implementCall(translator, call, implementor, nullAs));
return Expressions.foldAnd(list);
{code}
which should be
{code:java}
case FALSE:
// v0 != null && v1 != null && f(v0, v1)
for (Ord<RexNode> operand : Ord.zip(call.getOperands())) {
if (translator.isNullable(operand.e)) {
list.add(Expressions.notEqual(translator.translate(
operand.e, NullAs.IS_NOT_NULL), Expressions.constant(null)));
translator = translator.setNullable(operand.e, false);
}
}
list.add(implementCall(translator, call, implementor, nullAs));
return Expressions.foldAnd(list);
{code}
I fixed this in my branch and would submit this together with the PR I'm
preparing for the match recognize.
But it would be cool if you could also check if this is the correct solution.
> Problem with Code Generation
> ----------------------------
>
> Key: CALCITE-2966
> URL: https://issues.apache.org/jira/browse/CALCITE-2966
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.20.0
> Reporter: Danny Chan
> Assignee: Danny Chan
> Priority: Major
> Fix For: 1.20.0
>
>
> From the mailing list:
> Hi all,
> I have some problems with the code generation from Linq4j which I'm unable to
> resolve myself.
> Basically, I want to translate a condition from Rex to a Linq4j expression to
> use it in generated code.
> In my example the Condition is from Match Recognize and in SQL is:
> `up."commission" > prev(up."commission")`.
>
> ```
> RexBuilder rexBuilder = new RexBuilder(implementor.getTypeFactory());
> RexProgramBuilder rexProgramBuilder = new
> RexProgramBuilder(physType.getRowType(), rexBuilder);
>
> rexProgramBuilder.addCondition(entry.getValue());
>
> final Expression condition =
> RexToLixTranslator.translateCondition(rexProgramBuilder.getProgram(),
> (JavaTypeFactory) getCluster().getTypeFactory(),
> builder2,
> inputGetter1,
> implementor.allCorrelateVariables,
> implementor.getConformance());
>
> builder2.add(Expressions.return_(null, condition));
> ```
>
> Here, the condition seems okay, it is: ">(PREV(UP.$4, 0), PREV(UP.$4, 1))",
> so it should be a comparison of two variables (I rewrite the PREV with a
> custom Input Getter".
> But, the generated code (for Janino) is:
>
> ```
> Object p1 = row_.get($L4J$C$0_1);
> org.apache.calcite.test.JdbcTest.Employee p0 =
> (org.apache.calcite.test.JdbcTest.Employee) p1;
> Object p3 = row_.get($L4J$C$1_1);
> org.apache.calcite.test.JdbcTest.Employee p2 =
> (org.apache.calcite.test.JdbcTest.Employee) p3;
> Object p5 = row_.get($L4J$C$0_1);
> org.apache.calcite.test.JdbcTest.Employee p4 =
> (org.apache.calcite.test.JdbcTest.Employee) p5;
> Object p7 = row_.get($L4J$C$1_1);
> org.apache.calcite.test.JdbcTest.Employee p6 =
> (org.apache.calcite.test.JdbcTest.Employee) p7;
> return p0.commission && p2.commission && p4.commission > p6.commission;
> ```
>
> This confuses me a lot as I do not know where the check for p0.commission and
> p2.commission comes from.
> It seems that Linq4j adds them as it expects these variables to be nullable,
> but I have no idea on how to avoid this.
> These fields are Numeric so I always get a compilation exception.
>
> Can someone help me with this issue?
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