xiedeyantu commented on code in PR #4400:
URL: https://github.com/apache/calcite/pull/4400#discussion_r2133881000
##########
core/src/test/java/org/apache/calcite/test/RexImplicationCheckerTest.java:
##########
@@ -360,6 +361,135 @@ public class RexImplicationCheckerTest {
hasToString("2014"));
}
+ /** Test case for
+ * <a
href="https://issues.apache.org/jira/browse/CALCITE-7042";>[CALCITE-7042]
+ * Eliminate nested TRIM calls, exploiting the fact that TRIM is
idempotent</a>. */
+ @Test void testSimplifyIdempotentFunctions() {
+ final Fixture f = new Fixture();
+ RexLiteral trimBoth = f.rexBuilder.makeLiteral("BOTH");
+ RexLiteral trimed = f.rexBuilder.makeLiteral("a");
+ RexLiteral trimString = f.rexBuilder.makeLiteral("bb");
+
+ // trim way and string are the same
+ RexCall innerTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimBoth,
trimed, trimString);
+ RexCall outerTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimBoth,
trimed, innerTrimCall);
+ RexCall trimSimplifiedCall =
+ (RexCall) f.simplify.simplifyPreservingType(outerTrimCall,
+ RexUnknownAs.UNKNOWN, true);
+
+ // after simplify trimSimplifiedCall is equal to innerTrimCall
+ assertThat(trimSimplifiedCall.getKind(), is(SqlKind.TRIM));
+ assertThat(((RexLiteral) trimSimplifiedCall.getOperands().get(1))
+ .getValue(),
+ is(((RexLiteral) innerTrimCall.getOperands().get(1)).getValue()));
+ assertThat(((RexLiteral) trimSimplifiedCall.getOperands().get(2))
+ .getValue(),
+ is(((RexLiteral) innerTrimCall.getOperands().get(2)).getValue()));
+
+ // trim string are expression
+ final RelDataType integer =
+ f.rexBuilder.getTypeFactory().createSqlType(SqlTypeName.INTEGER);
+ final RexNode lengthArg = f.rexBuilder.makeLiteral(1, integer, true);
+ RexNode expressionTrim =
+ f.rexBuilder.makeCall(SqlStdOperatorTable.SUBSTRING, trimed,
lengthArg);
+ innerTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimBoth,
+ expressionTrim, trimString);
+ outerTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimBoth,
+ expressionTrim, innerTrimCall);
+ trimSimplifiedCall =
+ (RexCall) f.simplify.simplifyPreservingType(outerTrimCall,
+ RexUnknownAs.UNKNOWN, true);
+ // after simplify trimSimplifiedCall is equal to innerTrimCall
+ assertThat(trimSimplifiedCall.getOperands().get(1),
+ is(innerTrimCall.getOperands().get(1)));
+ assertThat(trimSimplifiedCall.getOperands().get(2),
+ is(innerTrimCall.getOperands().get(2)));
+
+ // Negative test of trim way is not the same
+ RexLiteral trimLeft = f.rexBuilder.makeLiteral("LEADING");
+ innerTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimBoth,
trimed, trimString);
+ RexCall outerLeftTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimLeft,
trimed, innerTrimCall);
+ trimSimplifiedCall =
+ (RexCall) f.simplify.simplifyPreservingType(outerLeftTrimCall,
+ RexUnknownAs.UNKNOWN, true);
+
+ // after simplify trimSimplifiedCall is not equal to innerTrimCall
+ assertThat(trimSimplifiedCall.getKind(), is(SqlKind.TRIM));
+ assertThat(((RexLiteral) trimSimplifiedCall.getOperands().get(1))
+ .getValue(),
+ is(((RexLiteral) innerTrimCall.getOperands().get(1)).getValue()));
+ assertThat(trimSimplifiedCall.getOperands().get(2),
+ is(innerTrimCall));
+
+ // Negative test of trimed string is null
+ RexLiteral trimNull = f.rexBuilder.makeNullLiteral(trimString.getType());
+ innerTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimBoth,
trimNull, trimString);
+ RexCall outerNullTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimLeft,
trimed, innerTrimCall);
+ RexNode trimSimplifiedNullCall =
+ f.simplify.simplifyPreservingType(outerNullTrimCall,
+ RexUnknownAs.UNKNOWN, true);
+ // after simplify trimSimplifiedCall is equal to null
+ assertThat(trimSimplifiedNullCall, hasToString("null:VARCHAR(2)"));
+
+ // Negative test of string is null
+ trimNull = f.rexBuilder.makeNullLiteral(trimString.getType());
+ innerTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimBoth,
trimed, trimNull);
+ outerNullTrimCall =
+ (RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimLeft,
trimed, innerTrimCall);
+ trimSimplifiedNullCall =
+ f.simplify.simplifyPreservingType(outerNullTrimCall,
+ RexUnknownAs.UNKNOWN, true);
+ // after simplify trimSimplifiedCall is equal to null
+ assertThat(trimSimplifiedNullCall, hasToString("null:VARCHAR(2)"));
+
+ final RexNode literalTs =
Review Comment:
```suggestion
// simplifyTrim supports recursive simplification
RelDataType varcharType =
f.typeFactory.createSqlType(SqlTypeName.VARCHAR);
// castCall is CAST(CAST(1111):VARCHAR NOT NULL):VARCHAR NOT NULL
final RexNode castCall =
f.cast(varcharType,
f.cast(varcharType, f.literal(1111)));
innerTrimCall =
(RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimBoth,
trimed, castCall);
// outerTrimCall is
// TRIM('BOTH', 'a', TRIM('BOTH', 'a', CAST(CAST(1111):VARCHAR NOT
NULL):VARCHAR NOT NULL))
outerTrimCall =
(RexCall) f.rexBuilder.makeCall(SqlStdOperatorTable.TRIM, trimBoth,
trimed, innerTrimCall);
trimSimplifiedCall =
(RexCall) f.simplify.simplifyPreservingType(outerTrimCall,
RexUnknownAs.UNKNOWN, true);
assertThat(trimSimplifiedCall,
hasToString("TRIM('BOTH', 'a', '1111':VARCHAR)"));
```
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