MVStore: use a different free space algorithm (pluggable now)

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

@@ -952,7 +952,8 @@ public class MVStore {
 
         // free up the space of unused chunks now
         for (Chunk x : removedChunks) {
-            freeSpace.free(x.start, x.length);
+            int len = MathUtils.roundUpInt(x.length, BLOCK_SIZE) + BLOCK_SIZE;
+            freeSpace.free(x.start, len);
         }
 
         c.start = filePos;
@@ -1617,7 +1618,8 @@ public class MVStore {
                 loadFromFile = true;
                 do {
                     last = chunks.remove(lastChunkId);
-                    freeSpace.free(last.start, last.length);
+                    int len = MathUtils.roundUpInt(last.length, BLOCK_SIZE) + BLOCK_SIZE;
+                    freeSpace.free(last.start, len);
                     lastChunkId--;
                 } while (last.version > version && chunks.size() > 0);
                 rootChunkStart = last.start;

h2/src/test/org/h2/test/store/TestMVTableEngine.java

@@ -72,6 +72,8 @@ public class TestMVTableEngine extends TestBase {
         Connection conn;
         Statement stat;
         long maxSize = 0;
+        // TODO does not shrink for 45 seconds; 
+        // need an option to configure that
         for (int i = 0; i < 20; i++) {
             conn = getConnection(dbName);
             stat = conn.createStatement();

h2/src/test/org/h2/test/store/TestTransactionStore.java

@@ -45,7 +45,7 @@ public class TestTransactionStore extends TestBase {
     @Override
     public void test() throws Exception {
         FileUtils.createDirectories(getBaseDir());
-        // testStopWhileCommitting();
+        testStopWhileCommitting();
         testGetModifiedMaps();
         testKeyIterator();
         testMultiStatement();