[CALCITE-6874] FilterCalcMergeRule/ProjectCalcMergeRule should not merge a Filter/Project to Calc when it contains Subquery

Author: NobiGo

core/src/main/java/org/apache/calcite/rel/rules/FilterCalcMergeRule.java

@@ -24,6 +24,7 @@
 import org.apache.calcite.rex.RexBuilder;
 import org.apache.calcite.rex.RexProgram;
 import org.apache.calcite.rex.RexProgramBuilder;
+import org.apache.calcite.rex.RexUtil;
 import org.apache.calcite.tools.RelBuilderFactory;
 
 import org.immutables.value.Value;
@@ -105,8 +106,9 @@ public interface Config extends RelRule.Config {
     default Config withOperandFor(Class<? extends Filter> filterClass,
         Class<? extends Calc> calcClass) {
       return withOperandSupplier(b0 ->
-          b0.operand(filterClass).oneInput(b1 ->
-              b1.operand(calcClass).anyInputs()))
+          b0.operand(filterClass)
+              .predicate(filter -> !RexUtil.SubQueryFinder.containsSubQuery(filter))
+              .oneInput(b1 -> b1.operand(calcClass).anyInputs()))
           .as(Config.class);
     }
   }

core/src/main/java/org/apache/calcite/rel/rules/ProjectCalcMergeRule.java

@@ -28,6 +28,7 @@
 import org.apache.calcite.rex.RexOver;
 import org.apache.calcite.rex.RexProgram;
 import org.apache.calcite.rex.RexProgramBuilder;
+import org.apache.calcite.rex.RexUtil;
 import org.apache.calcite.tools.RelBuilderFactory;
 import org.apache.calcite.util.Pair;
 
@@ -120,8 +121,9 @@ public interface Config extends RelRule.Config {
     default Config withOperandFor(Class<? extends Project> projectClass,
         Class<? extends Calc> calcClass) {
       return withOperandSupplier(b0 ->
-          b0.operand(projectClass).oneInput(b1 ->
-              b1.operand(calcClass).anyInputs()))
+          b0.operand(projectClass)
+              .predicate(project -> !RexUtil.SubQueryFinder.containsSubQuery(project))
+              .oneInput(b1 -> b1.operand(calcClass).anyInputs()))
           .as(Config.class);
     }
   }

core/src/test/java/org/apache/calcite/test/RelOptRulesTest.java

@@ -9711,6 +9711,37 @@ private void checkJoinAssociateRuleWithTopAlwaysTrueCondition(boolean allowAlway
         .check();
   }
 
+  /**
+   * Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE-6874">[CALCITE-6874]
+   * FilterCalcMergeRule/ProjectCalcMergeRule should not merge a Filter/Project to Calc
+   * when it contains Subquery</a>. */
+  @Test void testFilterCalcMergeRule() {
+    final String sql = "select deptno from sales.emp where\n"
+        + "exists (select deptno from sales.emp where empno < 20)\n";
+    HepProgram program = new HepProgramBuilder()
+        .addRuleInstance(CoreRules.PROJECT_FILTER_TRANSPOSE)
+        .addRuleInstance(CoreRules.PROJECT_TO_CALC)
+        .build();
+    sql(sql)
+        .withPre(program)
+        .withRule(CoreRules.FILTER_CALC_MERGE)
+        .checkUnchanged();
+  }
+
+  @Test void testProjectCalcMergeRule() {
+    final String sql = "select exists (select deptno from sales.emp)\n"
+        + "from (select deptno from sales.emp where empno < 20)\n";
+    HepProgram program = new HepProgramBuilder()
+        .addRuleInstance(CoreRules.PROJECT_FILTER_TRANSPOSE)
+        .addRuleInstance(CoreRules.FILTER_TO_CALC)
+        .build();
+    sql(sql)
+        .withPre(program)
+        .withRule(CoreRules.PROJECT_CALC_MERGE)
+        .checkUnchanged();
+  }
+
   /**
    * Test case of
    * <a href="https://issues.apache.org/jira/browse/CALCITE-6850">[CALCITE-6850]

core/src/test/resources/org/apache/calcite/test/RelOptRulesTest.xml

@@ -5100,6 +5100,23 @@ MyProject(EMPNO=[$0], ENAME=[$1], JOB=[$2], MGR=[$3], HIREDATE=[$4], SAL=[$5], C
 MultiJoin(joinFilter=[true], isFullOuterJoin=[false], joinTypes=[[INNER, LEFT]], outerJoinConditions=[[NULL, =($7, $9)]], projFields=[[{0, 1, 2, 3, 4, 5, 6, 7, 8}, {0, 1}]], postJoinFilter=[>($9, 3)])
   LogicalTableScan(table=[[CATALOG, SALES, EMP]])
   LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
+]]>
+    </Resource>
+  </TestCase>
+  <TestCase name="testFilterCalcMergeRule">
+    <Resource name="sql">
+      <![CDATA[select deptno from sales.emp where
+exists (select deptno from sales.emp where empno < 20)
+]]>
+    </Resource>
+    <Resource name="planBefore">
+      <![CDATA[
+LogicalFilter(condition=[EXISTS({
+LogicalFilter(condition=[<($0, 20)])
+  LogicalTableScan(table=[[CATALOG, SALES, EMP]])
+})])
+  LogicalCalc(expr#0..8=[{inputs}], DEPTNO=[$t7])
+    LogicalTableScan(table=[[CATALOG, SALES, EMP]])
 ]]>
     </Resource>
   </TestCase>
@@ -8643,6 +8660,23 @@ LogicalProject(EXPR$0=[*($0, 2)], SS0=[$1])
   LogicalAggregate(group=[{}], SUM_SAL=[SUM($0)], agg#1=[$SUM0($0)])
     LogicalProject(SAL=[$5])
       LogicalTableScan(table=[[CATALOG, SALES, EMP]])
+]]>
+    </Resource>
+  </TestCase>
+  <TestCase name="testProjectCalcMergeRule">
+    <Resource name="sql">
+      <![CDATA[select exists (select deptno from sales.emp)
+from (select deptno from sales.emp where empno < 20)
+]]>
+    </Resource>
+    <Resource name="planBefore">
+      <![CDATA[
+LogicalProject(EXPR$0=[EXISTS({
+LogicalTableScan(table=[[CATALOG, SALES, EMP]])
+})])
+  LogicalCalc(expr#0=[{inputs}], expr#1=[20], expr#2=[<($t0, $t1)], EMPNO=[$t0], $condition=[$t2])
+    LogicalProject(EMPNO=[$0])
+      LogicalTableScan(table=[[CATALOG, SALES, EMP]])
 ]]>
     </Resource>
   </TestCase>