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https://issues.apache.org/jira/browse/CALCITE-3562?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16988170#comment-16988170
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Julian Hyde commented on CALCITE-3562:
--------------------------------------
Too long for me to read all of this, but I think you are confusing user-defined
functions and internal functions.
* User-defined functions have argument types such as BigDecimal, Timestamp,
Date. They aim to be convenient, not necessarily performant.
* Internal functions, which occur in {{class SqlFunctions}}, and are only used
by code generation, and operate on internal types. DATE is represented as
{{int}}. TIMESTAMP is represented as {{long}}. DECIMAL is represented as
{{long}}.
> Unify function's operands type check logic in validation and behavior in
> runtime
> --------------------------------------------------------------------------------
>
> Key: CALCITE-3562
> URL: https://issues.apache.org/jira/browse/CALCITE-3562
> Project: Calcite
> Issue Type: Task
> Components: core
> Reporter: Feng Zhu
> Priority: Major
>
> Current now, there are many issues caused by inconsistency between validator
> and runtime phase. To summarize:
> (1)Validation phase allows a wide range of operand types, but the runtime
> implementation does not cover all cases.
> For example, _*SqlFunction(MOD)*_ adopts
> _*OperandTypes.EXACT_NUMERIC_EXACT_NUMERIC*_.
> {code:java}
> @Test public void test0() {
> final String sql = "SELECT mod(12.5, cast(1 as bigint))";
> CalciteAssert.that()
> .query(sql)
> .returns("EXPR$0=0.5\n");
> }{code}
> We will get:
> {code:java}
> java.lang.RuntimeException: while resolving method 'mod[class
> java.math.BigDecimal, long]' in class class
> org.apache.calcite.runtime.SqlFunctions
> at org.apache.calcite.linq4j.tree.Types.lookupMethod(Types.java:323)
> at org.apache.calcite.linq4j.tree.Expressions.call(Expressions.java:445)
> at
> org.apache.calcite.adapter.enumerable.RexImpTable$MethodNameImplementor.implement(RexImpTable.java:2253)
> at
> org.apache.calcite.adapter.enumerable.RexImpTable.implementCall(RexImpTable.java:1195){code}
>
> (2)Type is assignable conceptually, but in the runtime phase, explicite cast
> is still required.
> For example, according to _*SqlTypeAssignmentRules*_,
> *_ST_MakePoint(Decimal, Decimal)_* also accepts operands with (_Integer_,
> _Decimal_) types, because Decimal is assignable from Integer.
> {code:java}
> @Test public void test1() {
> final String sql = "SELECT ST_MakePoint(1, 2.1)";
> CalciteAssert.that()
> .with(CalciteAssert.Config.GEO)
> .query(sql)
> .returns("EXPR$0={\"x\":1,\"y\":2.1}\n");
> }
> {code}
> We will get:
> {code:java}
> org.codehaus.commons.compiler.CompileException: Line 22, Column 124: No
> applicable constructor/method found for actual parameters "int,
> java.math.BigDecimal"; candidates are: "public static
> org.apache.calcite.runtime.GeoFunctions$Geom
> org.apache.calcite.runtime.GeoFunctions.ST_MakePoint(java.math.BigDecimal,
> java.math.BigDecimal, java.math.BigDecimal)", "public static
> org.apache.calcite.runtime.GeoFunctions$Geom
> org.apache.calcite.runtime.GeoFunctions.ST_MakePoint(java.math.BigDecimal,
> java.math.BigDecimal)"
> at org.codehaus.janino.UnitCompiler.compileError(UnitCompiler.java:12211)
> at
> org.codehaus.janino.UnitCompiler.findMostSpecificIInvocable(UnitCompiler.java:9263)
> at org.codehaus.janino.UnitCompiler.findIMethod(UnitCompiler.java:9123)
> at org.codehaus.janino.UnitCompiler.findIMethod(UnitCompiler.java:9025)
> at org.codehaus.janino.UnitCompiler.compileGet2(UnitCompiler.java:5062)
> at org.codehaus.janino.UnitCompiler.access$9100(UnitCompiler.java:215){code}
>
> (3)For some functions, it is too late to fail the query in runtime phase.
> For example: _*RAND_INTEGER*_ adopts _*OperandTypes.or(OperandTypes.NUMERIC,
> OperandTypes.NUMERIC_NUMERIC)*_
> {code:java}
> @Test public void test2() {
> final String sql = "SELECT rand_integer(1.1, 2)";
> CalciteAssert.that()
> .query(sql)
> .planContains("xyxyx")
> .returns("EXPR$0={\"x\":1,\"y\":2.1}\n");
> }{code}
> We will get:
> {code:java}
> org.codehaus.commons.compiler.CompileException: Line 22, Column 100: No
> applicable constructor/method found for actual parameters
> "java.math.BigDecimal, int"; candidates are: "public int
> org.apache.calcite.runtime.RandomFunction.randIntegerSeed(int, int)"
> at org.codehaus.janino.UnitCompiler.compileError(UnitCompiler.java:12211)
> at
> org.codehaus.janino.UnitCompiler.findMostSpecificIInvocable(UnitCompiler.java:9263)
> at org.codehaus.janino.UnitCompiler.findIMethod(UnitCompiler.java:9123){code}
>
> *How to fix?*
> From my personal view, for case (1) and (2), we need to fix it in runtime
> layer with a "try-best" mechanism to convert operand type to match the
> implementation.
> The difference between them: case(1) is builtin function, we cannot get exact
> argument types, while case(2) is udf.
> For case(3), it seems more suitable to fix in Validation phase.
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