New experimental feature "SHUTDOWN DEFRAG". This option optimizes the page layout so

    that a full table scan is faster.

h2/src/main/org/h2/store/PageStore.java

@@ -524,11 +524,14 @@ public class PageStore implements CacheWriter {
                 ri.close();
             }
             recordPageReads = false;
+            int free = getFirstFree(); // We swap, so this page is fix
+            if (free == -1) {
+                DbException.throwInternalError("no free page for defrag");
+            } else {
                 int currentSeqPosInDb = MIN_PAGE_COUNT;
                 for (int i = 0; i < recordedPagesList.size(); i++) {
                     writeBack();
                     cache.clear();
-                int free = getFirstFree();
                     int a = currentSeqPosInDb;
                     int b = recordedPagesList.get(i);
 
@@ -546,11 +549,11 @@ public class PageStore implements CacheWriter {
                     }
                     recordedPagesList.set(i, a);
 
-                // Find next PageDataLeaf
                     while (true) {
                         currentSeqPosInDb++;
                         if (currentSeqPosInDb >= pageCount) {
                             currentSeqPosInDb = -1;
+                            break;
                         }
                         Page currentPage = getPage(currentSeqPosInDb);
                         if (currentPage == null) {
@@ -561,6 +564,7 @@ public class PageStore implements CacheWriter {
                         }
                     }
                 }
+            }
 
             recordedPagesList = null;
             recordedPagesSet = null;