MVStore file format documentation.

h2/src/docsrc/html/mvstore.html

@@ -510,23 +510,20 @@ s.close();
 will result in the following two chunks (excluding metadata):
 </p>
 <p>
-<b>Chunk 1:</b>
+<b>Chunk 1:</b><br />
+- Page 1: leaf with 140 entries (keys 0 - 139)<br />
+- Page 2: leaf with 260 entries (keys 140 - 399)<br />
+- Page 3: (root) node with 2 entries pointing to page 1 and 2<br />
 </p>
-<ul><li>Page 1: leaf with 140 entries (keys 0 - 139)
-</li><li>Page 2: leaf with 260 entries (keys 140 - 399)
-</li><li>Page 3: node with 2 entries pointing to page 1 and 2 (the root)
-</li></ul>
 <p>
-<b>Chunk 2:</b>
+<b>Chunk 2:</b><br />
+- Page 4: leaf with 140 entries (keys 0 - 139)<br />
+- Page 5: (root) node with 2 entries pointing to page 4 and 2<br />
 </p>
-<ul><li>Page 4: leaf with 140 entries (keys 0 - 139)
-</li><li>Page 5: node with 2 entries pointing to page 4 and 1 (the root)
-</li></ul>
 <p>
-That means each chunk contains the changes of one version,
-that means the new version of the changed pages and the parent pages,
-recursively, up to the root page. Pages in subsequent chunks refer to
-pages in earlier chunks.
+That means each chunk contains the changes of one version:
+the new version of the changed pages and the parent pages, recursively, up to the root page. 
+Pages in subsequent chunks refer to pages in earlier chunks.
 </p>
 
 <h3>File Header</h3>

h2/src/main/org/h2/mvstore/MVStore.java

@@ -657,13 +657,13 @@ public class MVStore {
      * @return the chunk, or null if not successful
      */
     private Chunk readChunkFooter(long end) {
-        // read the chunk footer of the last block of the file
-        ByteBuffer lastBlock = fileStore.readFully(
-                end - Chunk.FOOTER_LENGTH, Chunk.FOOTER_LENGTH);
-        byte[] buff = new byte[Chunk.FOOTER_LENGTH];
-        lastBlock.get(buff);
         // the following can fail for various reasons
         try {
+            // read the chunk footer of the last block of the file
+            ByteBuffer lastBlock = fileStore.readFully(
+                    end - Chunk.FOOTER_LENGTH, Chunk.FOOTER_LENGTH);
+            byte[] buff = new byte[Chunk.FOOTER_LENGTH];
+            lastBlock.get(buff);
             String s = new String(buff, DataUtils.LATIN).trim();
             HashMap<String, String> m = DataUtils.parseMap(s);
             int check = DataUtils.readHexInt(m, "fletcher", 0);

h2/src/test/org/h2/test/utils/FilePathUnstable.java

@@ -299,5 +299,10 @@ class FileUnstable extends FileBase {
     public synchronized FileLock tryLock(long position, long size, boolean shared) throws IOException {
         return channel.tryLock(position, size, shared);
     }
+    
+    @Override
+    public String toString() {
+        return "unstable:" + file.toString();
+    }
 
 }
\ No newline at end of file