Do not create default window frame if it was not set

h2/src/main/org/h2/expression/aggregate/AbstractAggregate.java

@@ -426,7 +426,7 @@ public abstract class AbstractAggregate extends Expression {
     protected void getOrderedResultLoop(Session session, HashMap<Integer, Value> result, ArrayList<Value[]> ordered,
             int rowIdColumn) {
         WindowFrame frame = over.getWindowFrame();
-        if (frame.isDefault()) {
+        if (frame == null || frame.isDefault()) {
             Object aggregateData = createAggregateData();
             for (Value[] row : ordered) {
                 updateFromExpressions(session, aggregateData, row);

h2/src/main/org/h2/expression/aggregate/Window.java

@@ -64,11 +64,6 @@ public final class Window {
     public Window(ArrayList<Expression> partitionBy, ArrayList<SelectOrderBy> orderBy, WindowFrame frame) {
         this.partitionBy = partitionBy;
         this.orderBy = orderBy;
-        if (frame == null) {
-            frame = new WindowFrame(WindowFrameUnits.RANGE,
-                    new WindowFrameBound(WindowFrameBoundType.UNBOUNDED_PRECEDING, null), null,
-                    WindowFrameExclusion.EXCLUDE_NO_OTHERS);
-        }
         this.frame = frame;
     }
 
@@ -146,9 +141,9 @@ public final class Window {
     }
 
     /**
-     * Returns window frame.
+     * Returns window frame, or null.
      *
-     * @return window frame
+     * @return window frame, or null
      */
     public WindowFrame getWindowFrame() {
         return frame;
@@ -196,7 +191,7 @@ public final class Window {
             }
         }
         appendOrderBy(builder, orderBy);
-        if (!frame.isDefault()) {
+        if (frame != null && !frame.isDefault()) {
             builder.append(' ').append(frame.getSQL());
         }
         return builder.append(')').toString();

h2/src/main/org/h2/expression/aggregate/WindowFrame.java

@@ -24,7 +24,7 @@ import org.h2.value.Value;
  */
 public final class WindowFrame {
 
-    private abstract class Itr implements Iterator<Value[]> {
+    private static abstract class Itr implements Iterator<Value[]> {
 
         final ArrayList<Value[]> orderedRows;
 
@@ -39,7 +39,7 @@ public final class WindowFrame {
 
     }
 
-    private final class PlainItr extends Itr {
+    private static final class PlainItr extends Itr {
 
         private final int endIndex;
 
@@ -66,7 +66,7 @@ public final class WindowFrame {
 
     }
 
-    private final class PlainReverseItr extends Itr {
+    private static final class PlainReverseItr extends Itr {
 
         private final int startIndex;
 
@@ -93,7 +93,7 @@ public final class WindowFrame {
 
     }
 
-    private abstract class AbstractBitSetItr extends Itr {
+    private static abstract class AbstractBitSetItr extends Itr {
 
         final BitSet set;
 
@@ -111,7 +111,7 @@ public final class WindowFrame {
 
     }
 
-    private final class BitSetItr extends AbstractBitSetItr {
+    private static final class BitSetItr extends AbstractBitSetItr {
 
         BitSetItr(ArrayList<Value[]> orderedRows, BitSet set) {
             super(orderedRows, set);
@@ -130,7 +130,7 @@ public final class WindowFrame {
 
     }
 
-    private final class BitSetReverseItr extends AbstractBitSetItr {
+    private static final class BitSetReverseItr extends AbstractBitSetItr {
 
         BitSetReverseItr(ArrayList<Value[]> orderedRows, BitSet set) {
             super(orderedRows, set);
@@ -157,6 +157,31 @@ public final class WindowFrame {
 
     private final WindowFrameExclusion exclusion;
 
+    /**
+     * Returns iterator for the specified frame, or default iterator if frame is
+     * null.
+     *
+     * @param frame
+     *            window frame, or null
+     * @param session
+     *            the session
+     * @param orderedRows
+     *            ordered rows
+     * @param sortOrder
+     *            sort order
+     * @param currentRow
+     *            index of the current row
+     * @param reverse
+     *            whether iterator should iterate in reverse order
+     *
+     * @return iterator
+     */
+    public static Iterator<Value[]> iterator(WindowFrame frame, Session session, ArrayList<Value[]> orderedRows,
+            SortOrder sortOrder, int currentRow, boolean reverse) {
+        return frame != null ? frame.iterator(session, orderedRows, sortOrder, currentRow, reverse)
+                : reverse ? new PlainReverseItr(orderedRows, 0, currentRow) : new PlainItr(orderedRows, 0, currentRow);
+    }
+
     private static int toGroupStart(ArrayList<Value[]> orderedRows, SortOrder sortOrder, int offset, int minOffset) {
         Value[] row = orderedRows.get(offset);
         while (offset > minOffset && sortOrder.compare(row, orderedRows.get(offset - 1)) == 0) {

h2/src/main/org/h2/expression/aggregate/WindowFunction.java

@@ -358,10 +358,12 @@ public class WindowFunction extends AbstractAggregate {
             Value v;
             switch (type) {
             case FIRST_VALUE:
-                v = getNthValue(frame.iterator(session, ordered, getOverOrderBySort(), i, false), 0, ignoreNulls);
+                v = getNthValue(WindowFrame.iterator(frame, session, ordered, getOverOrderBySort(), i, false), 0,
+                        ignoreNulls);
                 break;
             case LAST_VALUE:
-                v = getNthValue(frame.iterator(session, ordered, getOverOrderBySort(), i, true), 0, ignoreNulls);
+                v = getNthValue(WindowFrame.iterator(frame, session, ordered, getOverOrderBySort(), i, true), 0,
+                        ignoreNulls);
                 break;
             case NTH_VALUE: {
                 int n = row[1].getInt();
@@ -369,7 +371,8 @@ public class WindowFunction extends AbstractAggregate {
                     throw DbException.getInvalidValueException("nth row", n);
                 }
                 n--;
-                Iterator<Value[]> iter = frame.iterator(session, ordered, getOverOrderBySort(), i, fromLast);
+                Iterator<Value[]> iter = WindowFrame.iterator(frame, session, ordered, getOverOrderBySort(), i,
+                        fromLast);
                 v = getNthValue(iter, n, ignoreNulls);
                 break;
             }