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new 1e6b8cd1a9 [feature](nereids): SimplifyCastRule (#11630)
1e6b8cd1a9 is described below
commit 1e6b8cd1a916dba546a9f0268a8b45ec280b5916
Author: jakevin <[email protected]>
AuthorDate: Mon Aug 15 12:41:36 2022 +0800
[feature](nereids): SimplifyCastRule (#11630)
Remove redundant cast like
```
cast(1 as int) -> 1
```
---
.../rewrite/ExpressionNormalization.java | 4 +-
.../expression/rewrite/rules/SimplifyCastRule.java | 60 ++++++++++++++++++++++
.../doris/nereids/trees/expressions/Cast.java | 13 ++++-
.../expression/rewrite/ExpressionRewriteTest.java | 21 +++++++-
4 files changed, 93 insertions(+), 5 deletions(-)
diff --git
a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rewrite/ExpressionNormalization.java
b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rewrite/ExpressionNormalization.java
index 3cd9357325..465e120085 100644
---
a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rewrite/ExpressionNormalization.java
+++
b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rewrite/ExpressionNormalization.java
@@ -19,6 +19,7 @@ package org.apache.doris.nereids.rules.expression.rewrite;
import
org.apache.doris.nereids.rules.expression.rewrite.rules.BetweenToCompoundRule;
import
org.apache.doris.nereids.rules.expression.rewrite.rules.NormalizeBinaryPredicatesRule;
+import
org.apache.doris.nereids.rules.expression.rewrite.rules.SimplifyCastRule;
import
org.apache.doris.nereids.rules.expression.rewrite.rules.SimplifyNotExprRule;
import com.google.common.collect.ImmutableList;
@@ -33,7 +34,8 @@ public class ExpressionNormalization extends
ExpressionRewrite {
public static final List<ExpressionRewriteRule> NORMALIZE_REWRITE_RULES =
ImmutableList.of(
NormalizeBinaryPredicatesRule.INSTANCE,
BetweenToCompoundRule.INSTANCE,
- SimplifyNotExprRule.INSTANCE
+ SimplifyNotExprRule.INSTANCE,
+ SimplifyCastRule.INSTANCE
);
private static final ExpressionRuleExecutor EXECUTOR = new
ExpressionRuleExecutor(NORMALIZE_REWRITE_RULES);
diff --git
a/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rewrite/rules/SimplifyCastRule.java
b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rewrite/rules/SimplifyCastRule.java
new file mode 100644
index 0000000000..81d6e685ca
--- /dev/null
+++
b/fe/fe-core/src/main/java/org/apache/doris/nereids/rules/expression/rewrite/rules/SimplifyCastRule.java
@@ -0,0 +1,60 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.apache.doris.nereids.rules.expression.rewrite.rules;
+
+import
org.apache.doris.nereids.rules.expression.rewrite.AbstractExpressionRewriteRule;
+import
org.apache.doris.nereids.rules.expression.rewrite.ExpressionRewriteContext;
+import org.apache.doris.nereids.trees.expressions.Cast;
+import org.apache.doris.nereids.trees.expressions.Expression;
+
+
+/**
+ * Rewrite rule of simplify CAST expression.
+ * Remove redundant cast like
+ * - cast(1 as int) -> 1.
+ * Merge cast like
+ * - cast(cast(1 as bigint) as string) -> cast(1 as string).
+ */
+public class SimplifyCastRule extends AbstractExpressionRewriteRule {
+
+ public static SimplifyCastRule INSTANCE = new SimplifyCastRule();
+
+ @Override
+ public Expression visitCast(Cast origin, ExpressionRewriteContext context)
{
+ return simplify(origin);
+ }
+
+ private Expression simplify(Cast cast) {
+ Expression source = cast.left();
+ // simplify inside
+ if (source instanceof Cast) {
+ source = simplify((Cast) source);
+ }
+
+ // remove redundant cast
+ // CAST(value as type), value is type
+ if (cast.getDataType().equals(source.getDataType())) {
+ return source;
+ }
+
+ if (source != cast.left()) {
+ return new Cast(source, cast.right());
+ }
+ return cast;
+ }
+}
diff --git
a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Cast.java
b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Cast.java
index 63d0fd83c5..0e9839243a 100644
---
a/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Cast.java
+++
b/fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/Cast.java
@@ -34,9 +34,18 @@ public class Cast extends Expression implements
BinaryExpression {
super(child, new StringLiteral(type));
}
+ public Cast(Expression child, StringLiteral type) {
+ super(child, type);
+ }
+
+ @Override
+ public StringLiteral right() {
+ return (StringLiteral) BinaryExpression.super.right();
+ }
+
@Override
public DataType getDataType() {
- StringLiteral type = (StringLiteral) right();
+ StringLiteral type = right();
return DataType.convertFromString(type.getValue());
}
@@ -59,7 +68,7 @@ public class Cast extends Expression implements
BinaryExpression {
@Override
public String toSql() throws UnboundException {
- return "CAST(" + left().toSql() + " AS " + ((StringLiteral)
right()).getValue() + ")";
+ return "CAST(" + left().toSql() + " AS " + right().getValue() + ")";
}
@Override
diff --git
a/fe/fe-core/src/test/java/org/apache/doris/nereids/rules/expression/rewrite/ExpressionRewriteTest.java
b/fe/fe-core/src/test/java/org/apache/doris/nereids/rules/expression/rewrite/ExpressionRewriteTest.java
index eb94ec7ac6..80b42dd8de 100644
---
a/fe/fe-core/src/test/java/org/apache/doris/nereids/rules/expression/rewrite/ExpressionRewriteTest.java
+++
b/fe/fe-core/src/test/java/org/apache/doris/nereids/rules/expression/rewrite/ExpressionRewriteTest.java
@@ -22,6 +22,7 @@ import
org.apache.doris.nereids.rules.expression.rewrite.rules.BetweenToCompound
import
org.apache.doris.nereids.rules.expression.rewrite.rules.DistinctPredicatesRule;
import
org.apache.doris.nereids.rules.expression.rewrite.rules.ExtractCommonFactorRule;
import
org.apache.doris.nereids.rules.expression.rewrite.rules.NormalizeBinaryPredicatesRule;
+import
org.apache.doris.nereids.rules.expression.rewrite.rules.SimplifyCastRule;
import
org.apache.doris.nereids.rules.expression.rewrite.rules.SimplifyNotExprRule;
import org.apache.doris.nereids.trees.expressions.Expression;
@@ -144,11 +145,27 @@ public class ExpressionRewriteTest {
public void testBetweenToCompoundRule() {
executor = new
ExpressionRuleExecutor(ImmutableList.of(BetweenToCompoundRule.INSTANCE,
SimplifyNotExprRule.INSTANCE));
- assertRewrite(" a between c and d", "(a >= c) and (a <= d)");
- assertRewrite(" a not between c and d)", "(a < c) or (a > d)");
+ assertRewrite("a between c and d", "(a >= c) and (a <= d)");
+ assertRewrite("a not between c and d)", "(a < c) or (a > d)");
}
+ @Test
+ public void testSimplifyCastRule() {
+ executor = new
ExpressionRuleExecutor(ImmutableList.of(SimplifyCastRule.INSTANCE));
+
+ // deduplicate
+ assertRewrite("CAST(1 AS int)", "1");
+ assertRewrite("CAST(\"str\" AS string)", "\"str\"");
+ assertRewrite("CAST(CAST(1 AS int) AS int)", "1");
+
+ // deduplicate inside
+ assertRewrite("CAST(CAST(\"str\" AS string) AS double)", "CAST(\"str\"
AS double)");
+ assertRewrite("CAST(CAST(1 AS int) AS double)", "CAST(1 AS double)");
+
+ }
+
+
private void assertRewrite(String expression, String expected) {
Expression needRewriteExpression = PARSER.parseExpression(expression);
Expression expectedExpression = PARSER.parseExpression(expected);
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