[CALCITE-6947] Support LogicalSnapshot in RelShuttle

core/src/main/java/org/apache/calcite/rel/RelShuttle.java

@@ -28,6 +28,7 @@
 import org.apache.calcite.rel.logical.LogicalMatch;
 import org.apache.calcite.rel.logical.LogicalMinus;
 import org.apache.calcite.rel.logical.LogicalProject;
+import org.apache.calcite.rel.logical.LogicalSnapshot;
 import org.apache.calcite.rel.logical.LogicalSort;
 import org.apache.calcite.rel.logical.LogicalTableModify;
 import org.apache.calcite.rel.logical.LogicalUnion;
@@ -65,6 +66,8 @@ public interface RelShuttle {
 
   RelNode visit(LogicalSort sort);
 
+  RelNode visit(LogicalSnapshot snapshot);
+
   RelNode visit(LogicalExchange exchange);
 
   RelNode visit(LogicalTableModify modify);

core/src/main/java/org/apache/calcite/rel/RelShuttleImpl.java

@@ -29,6 +29,7 @@
 import org.apache.calcite.rel.logical.LogicalMatch;
 import org.apache.calcite.rel.logical.LogicalMinus;
 import org.apache.calcite.rel.logical.LogicalProject;
+import org.apache.calcite.rel.logical.LogicalSnapshot;
 import org.apache.calcite.rel.logical.LogicalSort;
 import org.apache.calcite.rel.logical.LogicalTableModify;
 import org.apache.calcite.rel.logical.LogicalUnion;
@@ -129,6 +130,10 @@ protected RelNode visitChildren(RelNode rel) {
     return visitChildren(sort);
   }
 
+  @Override public RelNode visit(LogicalSnapshot snapshot) {
+    return visitChildren(snapshot);
+  }
+
   @Override public RelNode visit(LogicalExchange exchange) {
     return visitChildren(exchange);
   }

core/src/main/java/org/apache/calcite/rel/logical/LogicalSnapshot.java

@@ -23,6 +23,7 @@
 import org.apache.calcite.rel.RelDistributionTraitDef;
 import org.apache.calcite.rel.RelInput;
 import org.apache.calcite.rel.RelNode;
+import org.apache.calcite.rel.RelShuttle;
 import org.apache.calcite.rel.core.Snapshot;
 import org.apache.calcite.rel.hint.RelHint;
 import org.apache.calcite.rel.metadata.RelMdCollation;
@@ -103,4 +104,9 @@ public static LogicalSnapshot create(RelNode input, RexNode period) {
   @Override public RelNode withHints(final List<RelHint> hintList) {
     return new LogicalSnapshot(getCluster(), traitSet, hintList, input, getPeriod());
   }
+
+  @Override public RelNode accept(RelShuttle shuttle) {
+    return shuttle.visit(this);
+  }
+
 }

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

@@ -35,6 +35,7 @@
 import org.apache.calcite.rel.externalize.RelXmlWriter;
 import org.apache.calcite.rel.logical.LogicalCalc;
 import org.apache.calcite.rel.logical.LogicalFilter;
+import org.apache.calcite.rel.logical.LogicalSnapshot;
 import org.apache.calcite.rel.logical.LogicalSort;
 import org.apache.calcite.rel.logical.LogicalTableModify;
 import org.apache.calcite.rel.rules.CoreRules;
@@ -2978,6 +2979,26 @@ void checkCorrelatedMapSubQuery(boolean expand) {
     assertThat(rels.get(0), instanceOf(LogicalCalc.class));
   }
 
+  /** Test case for
+   * <a href="https://issues.apache.org/jira/browse/CALCITE-6947">[CALCITE-6947]
+   * Support LogicalSnapshot in RelShuttle</a>. */
+  @Test void testRelShuttleForLogicalSnapshot() {
+    final String sql = "select * from products_temporal "
+        + "for system_time as of TIMESTAMP '2011-01-02 00:00:00'";
+    final RelNode rel = sql(sql).toRel();
+    final List<RelNode> rels = new ArrayList<>();
+    final RelShuttleImpl visitor = new RelShuttleImpl() {
+      @Override public RelNode visit(LogicalSnapshot modify) {
+        RelNode visitedRel = super.visit(modify);
+        rels.add(visitedRel);
+        return visitedRel;
+      }
+    };
+    rel.accept(visitor);
+    assertThat(rels, hasSize(1));
+    assertThat(rels.get(0), instanceOf(LogicalSnapshot.class));
+  }
+
   @Test void testRelShuttleForLogicalTableModify() {
     final String sql = "insert into emp select * from emp";
     final RelNode rel = sql(sql).toRel();