MVStore: improved error messages and logging; improved behavior if there is an…

MVStore: improved error messages and logging; improved behavior if there is an error when serializing objects.

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

@@ -92,8 +92,8 @@ public class Chunk {
 
     /**
      * When this chunk was no longer needed, in milliseconds after the store was
-     * created. After this, the chunk is kept alive for at least half the
-     * retention time (in case it is referenced in older versions).
+     * created. After this, the chunk is kept alive a bit longer (in case it is
+     * referenced in older versions).
      */
     public long unused;
 

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

@@ -42,6 +42,7 @@ TransactionStore:
     if there is only one connection
 
 MVStore:
+- make sure serialization / deserialization errors don't corrupt the file
 - FileStore: don't open and close when set using MVStore.Builder.fileStore
 - test and possibly improve compact operation (for large dbs)
 - is data kept in the stream store if the transaction is not committed?
@@ -115,6 +116,7 @@ MVStore:
 - rollback of removeMap should restore the data -
     which has big consequences, as the metadata map
     would probably need references to the root nodes of all maps
+- combine MVMap and MVMapConcurrent
 
 */
 
@@ -335,12 +337,7 @@ public class MVStore {
                 readFileHeader();
             }
         } catch (IllegalStateException e) {
-            try {
-                closeStore(false);
-            } catch (Exception e2) {
-                // ignore
-            }
-            throw e;
+            panic(e);
         } finally {
             if (encryptionKey != null) {
                 Arrays.fill(encryptionKey, (char) 0);
@@ -355,6 +352,15 @@ public class MVStore {
         setAutoCommitDelay(delay);
     }
     
+    private void panic(IllegalStateException e) {
+        try {
+            closeStore(false);
+        } catch (Exception e2) {
+            // ignore
+        }
+        throw e;
+    }
+
     /**
      * Open a store in exclusive mode. For a file-based store, the parent
      * directory must already exist.
@@ -1145,6 +1151,7 @@ public class MVStore {
             shrinkFileIfPossible(1);
         }
 
+        try {
             for (MVMap<?, ?> m : changed) {
                 Page p = m.getRoot();
                 if (p.getTotalCount() > 0) {
@@ -1152,6 +1159,9 @@ public class MVStore {
                 }
             }
             metaRoot.writeEnd();
+        } catch (IllegalStateException e) {
+            panic(e);
+        }
 
         // some pages might have been changed in the meantime (in the newest
         // version)

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

@@ -133,6 +133,8 @@ public class MVStoreTool {
                 int p = block.position();
                 pos += length;
                 int remaining = c.pageCount;
+                TreeMap<Integer, Integer> mapSizes = new TreeMap<Integer, Integer>();
+                int totalSize = 0;
                 while (remaining > 0) {
                     chunk.position(p);
                     int pageSize = chunk.getInt();
@@ -153,6 +155,12 @@ public class MVStoreTool {
                             node ? entries + 1 : entries,
                             pageSize);
                     p += pageSize;
+                    Integer mapSize = mapSizes.get(mapId);
+                    if (mapSize == null) {
+                        mapSize = 0;
+                    }
+                    mapSizes.put(mapId, mapSize + pageSize);
+                    totalSize += pageSize;
                     remaining--;
                     long[] children = null;
                     long[] counts = null;
@@ -219,6 +227,10 @@ public class MVStoreTool {
                         }
                     }
                 }
+                for (Integer mapId : mapSizes.keySet()) {
+                    int percent = 100 * mapSizes.get(mapId) / totalSize;
+                    pw.printf("map %x: %d%%%n", mapId, percent);
+                }
                 int footerPos = chunk.limit() - Chunk.FOOTER_LENGTH;
                 chunk.position(footerPos);
                 pw.printf(

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

@@ -91,7 +91,7 @@ public class StreamStore {
     }
 
     /**
-     * Store the stream, and return the id.
+     * Store the stream, and return the id. The stream is not closed.
      *
      * @param in the stream
      * @return the id (potentially an empty array)