save memory for in-memory databases

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

@@ -176,12 +176,17 @@ public class ScanIndex extends BaseIndex implements RowIndex {
             }
         } else {
             // in-memory
+            if (!database.isMultiVersion() && rowCount == 1) {
+                rows = new ObjectArray();
+                firstFree = -1;
+            } else {
                 Row free = new Row(null, 0);
                 free.setPos(firstFree);
                 int key = row.getPos();
                 rows.set(key, free);
                 firstFree = key;
             }
+        }
         if (database.isMultiVersion()) {
             // if storage is null, the delete flag is not yet set
             row.setDeleted(true);