libenchao commented on code in PR #3410:
URL: https://github.com/apache/calcite/pull/3410#discussion_r1337019127
##########
core/src/main/java/org/apache/calcite/rel/rules/CoreRules.java:
##########
@@ -745,6 +746,10 @@ private CoreRules() {}
public static final UnionToDistinctRule UNION_TO_DISTINCT =
UnionToDistinctRule.Config.DEFAULT.toRule();
+ /** Rule that rewrite {@link Sample} which is bernoulli to the {@link
Filter}. */
+ public static final RewriteSampleToFilterRule SAMPLE_TO_FILTER =
Review Comment:
We can add this rule the the default rule sets, e.g., in `BASE_RULES`?
##########
core/src/main/java/org/apache/calcite/rel/rules/RewriteSampleToFilterRule.java:
##########
@@ -0,0 +1,97 @@
+/*
+ * 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.calcite.rel.rules;
+
+import org.apache.calcite.plan.RelOptRuleCall;
+import org.apache.calcite.plan.RelRule;
+import org.apache.calcite.rel.core.Filter;
+import org.apache.calcite.rel.core.Sample;
+import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.sql.fun.SqlStdOperatorTable;
+import org.apache.calcite.tools.RelBuilder;
+
+import org.immutables.value.Value;
+
+/**
+ * This rule rewrite {@link Sample} which is bernoulli to the {@link Filter}.
+ *
+ * <p> For example:
+ * <blockquote><pre>{@code
+ * select deptno from "scott".dept tablesample bernoulli(50);
+ * }</pre></blockquote>
+ *
+ * <p> will convert to:
+ * <blockquote><pre>{@code
+ * select deptno from "scott".dept where rand() < 0.5;
+ * }</pre></blockquote>
+ *
+ * <p> The sql:
+ * <blockquote><pre>{@code
+ * select deptno from "scott".dept tablesample bernoulli(50) REPEATABLE(10);
+ * }</pre></blockquote>
+ *
+ * <p> will convert to:
+ * <blockquote><pre>{@code
+ * select deptno from "scott".dept where rand(10) < 0.5;
+ * }</pre></blockquote>
+ *
+ * @see CoreRules#SAMPLE_TO_FILTER
+ */
[email protected]
+public class RewriteSampleToFilterRule
Review Comment:
How about naming it `SampleToFilterRule`, it's precise enough. (We have
similar rules such as `JoinToCorrelateRule`, `FilterToCalcRule`)
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