When using SELECT_FOR_UPDATE_MVCC (lock only the selected rows when using MVCC),…

When using SELECT_FOR_UPDATE_MVCC (lock only the selected rows when using MVCC), the selected rows were sometimes not locked correctly.

h2/src/main/org/h2/command/dml/Select.java

@@ -504,7 +504,7 @@ public class Select extends Query {
                     row[i] = expr.getValue(session);
                 }
                 if (isForUpdateMvcc) {
-                    topTableFilter.lockRow(forUpdateRows);
+                    topTableFilter.lockRowAdd(forUpdateRows);
                 }
                 result.addRow(row);
                 rowNumber++;

h2/src/main/org/h2/result/Row.java

@@ -31,6 +31,22 @@ public class Row implements SearchRow {
         this.memory = memory;
     }
 
+    /**
+     * Get a copy of the row that is distinct from (not equal to) this row.
+     * This is used for FOR UPDATE to allow pseudo-updating a row.
+     *
+     * @return a new row with the same data
+     */
+    public Row getCopy() {
+        Value[] d2 = new Value[data.length];
+        System.arraycopy(data, 0, d2, 0, data.length);
+        Row r2 = new Row(d2, memory);
+        r2.key = key;
+        r2.version = version + 1;
+        r2.sessionId = sessionId;
+        return r2;
+    }
+
     public void setKeyAndVersion(SearchRow row) {
         setKey(row.getKey());
         setVersion(row.getVersion());

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

@@ -898,7 +898,7 @@ public class TableFilter implements ColumnResolver {
      *
      * @param rows the rows to lock
      */
-    public void lockRow(ArrayList<Row> rows) {
+    public void lockRowAdd(ArrayList<Row> rows) {
         if (state == FOUND) {
             rows.add(get());
         }
@@ -912,7 +912,8 @@ public class TableFilter implements ColumnResolver {
     public void lockRows(ArrayList<Row> forUpdateRows) {
         for (Row row : forUpdateRows) {
             table.removeRow(session, row);
-            table.addRow(session, row);
+            Row r2 = row.getCopy();
+            table.addRow(session, r2);
         }
     }