From d77a055e998b4fea726f8cc3c7bfd497ab697ac0 Mon Sep 17 00:00:00 2001
From: xiejiajun <jiajunbernoulli@foxmail.com>
Date: Sat, 13 Jan 2024 10:44:34 +0800
Subject: [PATCH] [CALCITE-6193] If a query has more than one subexpression
 that matches a materialized view, only the first is substituted

---
 .../calcite/plan/SubstitutionVisitor.java     |  7 +++-
 ...terializedViewSubstitutionVisitorTest.java | 37 +++++++++++++++++++
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java b/core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java
index 20683053210..17f707cee1e 100644
--- a/core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java
+++ b/core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java
@@ -559,7 +559,7 @@ assert rowTypesAreEquivalent(
 
     final List<Replacement> attempted = new ArrayList<>();
     List<List<Replacement>> substitutions = new ArrayList<>();
-
+    int globalInputIndex = 0;
     for (;;) {
       int count = 0;
       MutableRel queryDescendant = query;
@@ -575,9 +575,11 @@ assert rowTypesAreEquivalent(
           }
         }
         final MutableRel next = MutableRels.preOrderTraverseNext(queryDescendant);
+        final int currentInputIndex = queryDescendant.getInputs().size() > globalInputIndex
+            ? globalInputIndex : 0;
         final MutableRel childOrNext =
             queryDescendant.getInputs().isEmpty()
-                ? next : queryDescendant.getInputs().get(0);
+                ? next : queryDescendant.getInputs().get(currentInputIndex);
         for (MutableRel targetDescendant : targetDescendants) {
           for (UnifyRule rule
               : applicableRules(queryDescendant, targetDescendant)) {
@@ -616,6 +618,7 @@ assert rowTypesAreEquivalent(
                   substitutions.add(ImmutableList.copyOf(attempted));
                   attempted.clear();
                   queryDescendant = next;
+                  globalInputIndex++;
                   continue outer;
                 }
                 // We will try walking the query tree all over again to see
diff --git a/core/src/test/java/org/apache/calcite/test/MaterializedViewSubstitutionVisitorTest.java b/core/src/test/java/org/apache/calcite/test/MaterializedViewSubstitutionVisitorTest.java
index dca173b5719..c38fedc5638 100644
--- a/core/src/test/java/org/apache/calcite/test/MaterializedViewSubstitutionVisitorTest.java
+++ b/core/src/test/java/org/apache/calcite/test/MaterializedViewSubstitutionVisitorTest.java
@@ -1849,6 +1849,43 @@ protected final MaterializedViewFixture sql(String materialize,
     sql(mv2, query2).ok();
   }
 
+  /** Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE-6193">[CALCITE-6193]
+   * If a query has more than one subexpression that matches a materialized view,
+   * only the first is substituted</a>. */
+  @Test void testStopTryIncorrectSubtree() {
+    final String mv = ""
+        + "select \"empid\", \"deptno\"\n"
+        + "from \"emps\"\n"
+        + "group by \"empid\", \"deptno\"";
+    final String matchQuery = "select \"deptno\"\n"
+        + "from \"emps\"\n"
+        + "group by \"deptno\"\n";
+    final String query = ""
+        + "select t1.\"deptno\"\n"
+        + "from (\n"
+        + "select \"deptno\"\n"
+        + "from \"emps\"\n"
+        + "union all\n"
+        + matchQuery
+        + ") as t1 inner join (\n"
+        + matchQuery
+        + ") as t2 on t1.\"deptno\" = t2.\"deptno\"\n";
+    sql(mv, query)
+        .checkingThatResultContains(""
+            + "LogicalCalc(expr#0..1=[{inputs}], deptno=[$t0])\n"
+            + "  LogicalJoin(condition=[=($0, $1)], joinType=[inner])\n"
+            + "    LogicalUnion(all=[true])\n"
+            + "      LogicalCalc(expr#0..1=[{inputs}], deptno=[$t1])\n"
+            + "        LogicalCalc(expr#0..4=[{inputs}], proj#0..1=[{exprs}])\n"
+            + "          LogicalTableScan(table=[[hr, emps]])\n"
+            + "      LogicalAggregate(group=[{1}])\n"
+            + "        EnumerableTableScan(table=[[hr, MV0]])\n"
+            + "    LogicalAggregate(group=[{1}])\n"
+            + "      EnumerableTableScan(table=[[hr, MV0]])")
+        .ok();
+  }
+
   /** Fixture for tests for whether expressions are satisfiable,
    * specifically {@link SubstitutionVisitor#mayBeSatisfiable(RexNode)}. */
   private static class SatisfiabilityFixture {