[CALCITE-6947] Support LogicalSnapshot in RelShuttle

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

@@ -29,6 +29,7 @@
 import org.apache.calcite.rel.logical.LogicalMinus;
 import org.apache.calcite.rel.logical.LogicalProject;
 import org.apache.calcite.rel.logical.LogicalRepeatUnion;
+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;
@@ -91,6 +92,10 @@ public class RelHomogeneousShuttle extends RelShuttleImpl {
     return visit((RelNode) sort);
   }
 
+  @Override public RelNode visit(LogicalSnapshot snapshot) {
+    return visit((RelNode) snapshot);
+  }
+
   @Override public RelNode visit(LogicalExchange exchange) {
     return visit((RelNode) exchange);
   }

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

@@ -30,6 +30,7 @@
 import org.apache.calcite.rel.logical.LogicalMinus;
 import org.apache.calcite.rel.logical.LogicalProject;
 import org.apache.calcite.rel.logical.LogicalRepeatUnion;
+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;
@@ -67,6 +68,8 @@ 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

@@ -31,6 +31,7 @@
 import org.apache.calcite.rel.logical.LogicalMinus;
 import org.apache.calcite.rel.logical.LogicalProject;
 import org.apache.calcite.rel.logical.LogicalRepeatUnion;
+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;
@@ -131,6 +132,10 @@ 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/SqlHintsConverterTest.java

@@ -54,6 +54,7 @@
 import org.apache.calcite.rel.logical.LogicalJoin;
 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.LogicalUnion;
 import org.apache.calcite.rel.logical.LogicalValues;
@@ -919,6 +920,13 @@ private static class HintCollector extends RelShuttleImpl {
         return super.visit(sort);
       }
 
+      @Override public RelNode visit(LogicalSnapshot snapshot) {
+        if (!snapshot.getHints().isEmpty()) {
+          this.hintsCollect.add("Snapshot:" + snapshot.getHints());
+        }
+        return super.visit(snapshot);
+      }
+
       @Override public RelNode visit(LogicalValues values) {
         if (!values.getHints().isEmpty()) {
           this.hintsCollect.add("Values:" + values.getHints());

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

@@ -41,6 +41,7 @@
 import org.apache.calcite.rel.logical.LogicalCalc;
 import org.apache.calcite.rel.logical.LogicalFilter;
 import org.apache.calcite.rel.logical.LogicalRepeatUnion;
+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;
@@ -3086,6 +3087,36 @@ 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 List<RelNode> otherRels = new ArrayList<>();
+    final RelShuttleImpl visitor = new RelShuttleImpl() {
+      @Override public RelNode visit(LogicalSnapshot modify) {
+        RelNode visitedRel = super.visit(modify);
+        rels.add(visitedRel);
+        return visitedRel;
+      }
+
+      @Override public RelNode visit(RelNode other) {
+        if (other instanceof LogicalSnapshot) {
+          otherRels.add(other);
+        }
+        RelNode visitedRel = super.visit(other);
+        return visitedRel;
+      }
+    };
+    rel.accept(visitor);
+    assertThat(otherRels, hasSize(0));
+    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();

site/_docs/history.md

@@ -49,6 +49,11 @@ other software versions as specified in gradle.properties.
 #### Breaking Changes
 {: #breaking-1-42-0}
 
+* [<a href="https://issues.apache.org/jira/browse/CALCITE-6947">CALCITE-6947</a>]
+The feature support LogicalSnapshot in RelShuttle. please note that If there’s a class X that extends LogicalSnapshot
+and a class Y extends Snapshot, but not LogicalSnapshot, then X will call RelShuttle.visit(LogicalSnapshot)
+and Y will call RelShuttle.visit(RelNode other)
+
 #### New features
 {: #new-features-1-42-0}