Recursive queries with many rows could throw an IndexOutOfBoundsException.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,8 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>The auto-server mode can't be combined with an in-memory database.
+<ul><li>Recursive queries with many rows could throw an IndexOutOfBoundsException.
+</li><li>The auto-server mode can't be combined with an in-memory database.
     This invalid combination wasn't detected so far.
     Now trying to open a database in this way fails.
 </li><li>Improved performance for reading and writing date and time values.

h2/src/main/org/h2/index/ViewIndex.java

@@ -157,10 +157,10 @@ public class ViewIndex extends BaseIndex {
 
     public Cursor find(Session session, SearchRow first, SearchRow last) {
         if (recursive) {
-            if (view.getRecursiveResult() != null) {
-                ResultInterface r = view.getRecursiveResult();
-                r.reset();
-                return new ViewCursor(table, r);
+            ResultInterface recResult = view.getRecursiveResult(session);
+            if (recResult != null) {
+                recResult.reset();
+                return new ViewCursor(table, recResult);
             }
             if (query == null) {
                 query = (Query) createSession.prepare(querySQL, true);
@@ -174,14 +174,14 @@ public class ViewIndex extends BaseIndex {
                 throw DbException.get(ErrorCode.SYNTAX_ERROR_2, "recursive queries without UNION ALL");
             }
             Query left = union.getLeft();
-            ResultInterface r = left.query(0);
+            LocalResult r = left.query(0);
             LocalResult result = union.getEmptyResult();
             while (r.next()) {
                 result.addRow(r.currentRow());
             }
             Query right = union.getRight();
             r.reset();
-            view.setRecursiveResult(r);
+            view.setRecursiveResult(r, session);
             while (true) {
                 r = right.query(0);
                 if (r.getRowCount() == 0) {
@@ -191,7 +191,7 @@ public class ViewIndex extends BaseIndex {
                     result.addRow(r.currentRow());
                 }
                 r.reset();
-                view.setRecursiveResult(r);
+                view.setRecursiveResult(r, session);
             }
             return new ViewCursor(table, result);
         }

h2/src/main/org/h2/table/TableView.java

@@ -20,6 +20,7 @@ import org.h2.index.Index;
 import org.h2.index.IndexType;
 import org.h2.index.ViewIndex;
 import org.h2.message.DbException;
+import org.h2.result.LocalResult;
 import org.h2.result.ResultInterface;
 import org.h2.result.Row;
 import org.h2.schema.Schema;
@@ -50,7 +51,7 @@ public class TableView extends Table {
     private long maxDataModificationId;
     private User owner;
     private Query topQuery;
-    private ResultInterface recursiveResult;
+    private LocalResult recursiveResult;
     private boolean tableExpression;
 
     public TableView(Schema schema, int id, String name, String querySQL, ArrayList<Parameter> params, String[] columnNames,
@@ -443,12 +444,12 @@ public class TableView extends Table {
         return viewQuery.isEverything(ExpressionVisitor.DETERMINISTIC_VISITOR);
     }
 
-    public void setRecursiveResult(ResultInterface recursiveResult) {
-        this.recursiveResult = recursiveResult;
+    public void setRecursiveResult(LocalResult value, Session session) {
+        this.recursiveResult = value.createShallowCopy(session);
     }
 
-    public ResultInterface getRecursiveResult() {
-        return recursiveResult;
+    public ResultInterface getRecursiveResult(Session session) {
+        return recursiveResult == null ? null : recursiveResult.createShallowCopy(session);
     }
 
     public void setTableExpression(boolean tableExpression) {

h2/src/test/org/h2/test/db/TestRecursiveQueries.java

@@ -27,6 +27,34 @@ public class TestRecursiveQueries extends TestBase {
     }
 
     public void test() throws Exception {
+        testWrongLinkLargeResult();
+        testSimple();
+    }
+
+    private void testWrongLinkLargeResult() throws Exception {
+        deleteDb("recursiveQueries");
+        Connection conn = getConnection("recursiveQueries");
+        Statement stat;
+        stat = conn.createStatement();
+        stat.execute("create table test(parent varchar(255), child varchar(255))");
+        stat.execute("insert into test values('/', 'a'), ('a', 'b1'), ('a', 'b2'), ('a', 'c'), ('c', 'd1'), ('c', 'd2')");
+        // stat.execute("with recursive rec_test(depth, parent, child) as (" +
+        //        "select 0, parent, child from test where parent = '/' " +
+        //        "union all " +
+        //        "select depth+1, r.parent, r.child from test i join rec_test r " +
+        //        "on (i.parent = r.child) where depth<9 " +
+        //        ") select * from rec_test");
+        stat.execute("with recursive rec_test(depth, parent, child) as ( "+
+                "select 0, parent, child from test where parent = '/' "+
+                "union all "+
+                "select depth+1, i.parent, i.child from test i join rec_test r "+
+                "on (r.child = i.parent) where depth<10 "+
+                ") select * from rec_test");
+        conn.close();
+        deleteDb("recursiveQueries");
+    }
+
+    private void testSimple() throws Exception {
         deleteDb("recursiveQueries");
         Connection conn = getConnection("recursiveQueries");
         Statement stat;