MVStore: deal with the case that data was moved to a new chunk (work in progress)

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

@@ -795,16 +795,25 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      * @return whether rewriting was successful
      */
     boolean rewrite(Set<Integer> set) {
-        if (root.getVersion() < createVersion) {
+        // read from old version, to avoid concurrent reads
+        long previousVersion = store.getCurrentVersion() - 1;
+        if (previousVersion < createVersion) {
             // a new map
             return true;
         }
-        // read from old version, to avoid concurrent reads
-        MVMap<K, V> readMap = openVersion(root.getVersion() - 1);
+        MVMap<K, V> readMap;
+        try {
+            readMap = openVersion(previousVersion);
+        } catch (IllegalArgumentException e) {
+            // unknown version: ok
+            // TODO should not rely on exception handling
+            return true;
+        }
         try {
             rewrite(readMap.root, set);
             return true;
         } catch (IllegalStateException e) {
+            // TODO should not rely on exception handling
             if (DataUtils.getErrorCode(e.getMessage()) == DataUtils.ERROR_CHUNK_NOT_FOUND) {
                 // ignore
                 return false;

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

@@ -65,7 +65,7 @@ public class TestConcurrent extends TestMVStore {
         String fileName = "memFS:testConcurrentChangeAndBackgroundCompact";
         FileUtils.delete(fileName);
         final MVStore s = new MVStore.Builder().
-                fileName(fileName).pageSplitSize(100).
+                fileName(fileName).pageSplitSize(1000).
                 open();
         try {
             s.setRetentionTime(1000);

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

@@ -871,7 +871,8 @@ public class TestMVStore extends TestBase {
 
     private void testFileHeaderCorruption() throws Exception {
         String fileName = getBaseDir() + "/testFileHeader.h3";
-        MVStore s = openStore(fileName);
+        MVStore s = new MVStore.Builder().
+                fileName(fileName).pageSplitSize(1000).autoCommitDisabled().open();
         s.setRetentionTime(0);
         MVMap<Integer, byte[]> map;
         map = s.openMap("test");