A persistent multi-version map (work in progress) - rename to MVStore / MVMap

h2/src/test/org/h2/test/TestAll.java

@@ -105,7 +105,7 @@ import org.h2.test.server.TestWeb;
 import org.h2.test.server.TestInit;
 import org.h2.test.store.TestCacheLIRS;
 import org.h2.test.store.TestDataUtils;
-import org.h2.test.store.TestBtreeMapStore;
+import org.h2.test.store.TestMVStore;
 import org.h2.test.store.TestRtree;
 import org.h2.test.synth.TestBtreeIndex;
 import org.h2.test.synth.TestCrashAPI;
@@ -665,7 +665,7 @@ kill -9 `jps -l | grep "org.h2.test." | cut -d " " -f 1`
 
     private void testUnit() {
         // store
-        new TestBtreeMapStore().runTest(this);
+        new TestMVStore().runTest(this);
         new TestCacheLIRS().runTest(this);
         new TestDataUtils().runTest(this);
         new TestRtree().runTest(this);

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

@@ -7,8 +7,8 @@
 package org.h2.test.store;
 
 import java.util.ArrayList;
-import org.h2.dev.store.btree.BtreeMap;
-import org.h2.dev.store.btree.BtreeMapStore;
+import org.h2.dev.store.btree.MVMap;
+import org.h2.dev.store.btree.MVStore;
 import org.h2.dev.store.btree.Cursor;
 import org.h2.dev.store.btree.CursorPos;
 import org.h2.dev.store.btree.DataType;
@@ -21,12 +21,12 @@ import org.h2.util.New;
  * @param <K> the key class
  * @param <V> the value class
  */
-public class RtreeMap<K, V> extends BtreeMap<K, V> {
+public class RtreeMap<K, V> extends MVMap<K, V> {
 
     private final SpatialType keyType;
     private boolean quadraticSplit;
 
-    RtreeMap(BtreeMapStore store, int id, String name, DataType keyType,
+    RtreeMap(MVStore store, int id, String name, DataType keyType,
             DataType valueType, long createVersion) {
         super(store, id, name, keyType, valueType, createVersion);
         this.keyType = (SpatialType) keyType;

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

@@ -9,8 +9,8 @@ package org.h2.test.store;
 import java.util.AbstractSet;
 import java.util.Iterator;
 import java.util.Set;
-import org.h2.dev.store.btree.BtreeMap;
-import org.h2.dev.store.btree.BtreeMapStore;
+import org.h2.dev.store.btree.MVMap;
+import org.h2.dev.store.btree.MVStore;
 import org.h2.dev.store.btree.DataType;
 
 /**
@@ -19,11 +19,11 @@ import org.h2.dev.store.btree.DataType;
  * @param <K> the key type
  * @param <V> the key type
  */
-public class SequenceMap<K, V> extends BtreeMap<K, V> {
+public class SequenceMap<K, V> extends MVMap<K, V> {
 
     int min = 1, max = 10;
 
-    SequenceMap(BtreeMapStore store, int id, String name, DataType keyType,
+    SequenceMap(MVStore store, int id, String name, DataType keyType,
             DataType valueType, long createVersion) {
         super(store, id, name, keyType, valueType, createVersion);
         setReadOnly(true);

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

@@ -9,8 +9,8 @@ import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.Random;
 import java.util.TreeMap;
-import org.h2.dev.store.btree.BtreeMap;
-import org.h2.dev.store.btree.BtreeMapStore;
+import org.h2.dev.store.btree.MVMap;
+import org.h2.dev.store.btree.MVStore;
 import org.h2.jaqu.bytecode.Null;
 import org.h2.store.fs.FileUtils;
 import org.h2.test.TestBase;
@@ -19,7 +19,7 @@ import org.h2.util.New;
 /**
  * Tests the tree map store.
  */
-public class TestBtreeMapStore extends TestBase {
+public class TestMVStore extends TestBase {
 
     /**
      * Run just this test.
@@ -52,9 +52,9 @@ public class TestBtreeMapStore extends TestBase {
     private void testIterateOverChanges() {
         String fileName = getBaseDir() + "/testVersion.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = openStore(fileName);
+        MVStore s = openStore(fileName);
         s.setMaxPageSize(6);
-        BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
+        MVMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
         for (int i = 0; i < 60; i++) {
             m.put(i, "Hello");
         }
@@ -79,9 +79,9 @@ public class TestBtreeMapStore extends TestBase {
     private void testVersion() {
         String fileName = getBaseDir() + "/testVersion.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s;
+        MVStore s;
         s = openStore(fileName);
-        BtreeMap<String, String> m;
+        MVMap<String, String> m;
         s = openStore(fileName);
         m = s.openMap("data", String.class, String.class);
         long first = s.getCurrentVersion();
@@ -94,10 +94,10 @@ public class TestBtreeMapStore extends TestBase {
         long old = s.getCurrentVersion();
         m.put("1", "Hallo");
         m.put("2", "Welt");
-        BtreeMap<String, String> mFirst;
+        MVMap<String, String> mFirst;
         mFirst = m.openVersion(first);
         assertEquals(0, mFirst.size());
-        BtreeMap<String, String> mOld;
+        MVMap<String, String> mOld;
         assertEquals("Hallo", m.get("1"));
         assertEquals("Welt", m.get("2"));
         mOld = m.openVersion(old);
@@ -130,8 +130,8 @@ public class TestBtreeMapStore extends TestBase {
     private void testTruncateFile() {
         String fileName = getBaseDir() + "/testTruncate.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s;
-        BtreeMap<Integer, String> m;
+        MVStore s;
+        MVMap<Integer, String> m;
         s = openStore(fileName);
         m = s.openMap("data", Integer.class, String.class);
         for (int i = 0; i < 1000; i++) {
@@ -153,8 +153,8 @@ public class TestBtreeMapStore extends TestBase {
     private void testFastDelete() {
         String fileName = getBaseDir() + "/testFastDelete.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s;
-        BtreeMap<Integer, String> m;
+        MVStore s;
+        MVMap<Integer, String> m;
         s = openStore(fileName);
         s.setMaxPageSize(100);
         m = s.openMap("data", Integer.class, String.class);
@@ -181,16 +181,16 @@ public class TestBtreeMapStore extends TestBase {
     private void testRollbackStored() {
         String fileName = getBaseDir() + "/testRollback.h3";
         FileUtils.delete(fileName);
-        BtreeMap<String, String> meta;
-        BtreeMapStore s = openStore(fileName);
+        MVMap<String, String> meta;
+        MVStore s = openStore(fileName);
         assertEquals(-1, s.getRetainChunk());
         s.setRetainChunk(0);
         assertEquals(0, s.getRetainChunk());
         assertEquals(1, s.getCurrentVersion());
         assertFalse(s.hasUnsavedChanges());
-        BtreeMap<String, String> m = s.openMap("data", String.class, String.class);
+        MVMap<String, String> m = s.openMap("data", String.class, String.class);
         assertTrue(s.hasUnsavedChanges());
-        BtreeMap<String, String> m0 = s.openMap("data0", String.class, String.class);
+        MVMap<String, String> m0 = s.openMap("data0", String.class, String.class);
         m.put("1", "Hello");
         assertEquals(1, s.commit());
         s.rollbackTo(1);
@@ -207,7 +207,7 @@ public class TestBtreeMapStore extends TestBase {
         meta = s.getMetaMap();
         m = s.openMap("data", String.class, String.class);
         m0 = s.openMap("data0", String.class, String.class);
-        BtreeMap<String, String> m1 = s.openMap("data1", String.class, String.class);
+        MVMap<String, String> m1 = s.openMap("data1", String.class, String.class);
         m.put("1", "Hallo");
         m0.put("1", "Hallo");
         m1.put("1", "Hallo");
@@ -267,17 +267,17 @@ public class TestBtreeMapStore extends TestBase {
     private void testRollbackInMemory() {
         String fileName = getBaseDir() + "/testRollback.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = openStore(fileName);
+        MVStore s = openStore(fileName);
         assertEquals(1, s.getCurrentVersion());
         s.setMaxPageSize(5);
-        BtreeMap<String, String> m = s.openMap("data", String.class, String.class);
+        MVMap<String, String> m = s.openMap("data", String.class, String.class);
         s.rollbackTo(0);
         assertTrue(m.isClosed());
         assertEquals(1, s.getCurrentVersion());
         m = s.openMap("data", String.class, String.class);
 
-        BtreeMap<String, String> m0 = s.openMap("data0", String.class, String.class);
-        BtreeMap<String, String> m2 = s.openMap("data2", String.class, String.class);
+        MVMap<String, String> m0 = s.openMap("data0", String.class, String.class);
+        MVMap<String, String> m2 = s.openMap("data2", String.class, String.class);
         m.put("1", "Hello");
         for (int i = 0; i < 10; i++) {
             m2.put("" + i, "Test");
@@ -285,7 +285,7 @@ public class TestBtreeMapStore extends TestBase {
         long v1 = s.commit();
         assertEquals(1, v1);
         assertEquals(2, s.getCurrentVersion());
-        BtreeMap<String, String> m1 = s.openMap("data1", String.class, String.class);
+        MVMap<String, String> m1 = s.openMap("data1", String.class, String.class);
         assertEquals("Test", m2.get("1"));
         m.put("1", "Hallo");
         m0.put("1", "Hallo");
@@ -309,10 +309,10 @@ public class TestBtreeMapStore extends TestBase {
     private void testMeta() {
         String fileName = getBaseDir() + "/testMeta.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = openStore(fileName);
-        BtreeMap<String, String> m = s.getMetaMap();
+        MVStore s = openStore(fileName);
+        MVMap<String, String> m = s.getMetaMap();
         s.setRetainChunk(0);
-        BtreeMap<String, String> data = s.openMap("data", String.class, String.class);
+        MVMap<String, String> data = s.openMap("data", String.class, String.class);
         data.put("1", "Hello");
         data.put("2", "World");
         s.store();
@@ -332,13 +332,13 @@ public class TestBtreeMapStore extends TestBase {
 
     private void testInMemory() {
         for (int j = 0; j < 1; j++) {
-            BtreeMapStore s = openStore(null);
+            MVStore s = openStore(null);
             // s.setMaxPageSize(10);
             // long t;
             int len = 100;
             // TreeMap<Integer, String> m = new TreeMap<Integer, String>();
             // HashMap<Integer, String> m = New.hashMap();
-            BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
+            MVMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
             // t = System.currentTimeMillis();
             for (int i = 0; i < len; i++) {
                 m.put(i, "Hello World");
@@ -365,10 +365,10 @@ public class TestBtreeMapStore extends TestBase {
         int len = 1000;
         for (int j = 0; j < 5; j++) {
             FileUtils.delete(fileName);
-            BtreeMapStore s = openStore(fileName);
+            MVStore s = openStore(fileName);
             // s.setCompressor(null);
             s.setMaxPageSize(40);
-            BtreeMap<Integer, Object[]> m = s.openMap("data", "", "i", "r(i,,)");
+            MVMap<Integer, Object[]> m = s.openMap("data", "", "i", "r(i,,)");
             // Profiler prof = new Profiler();
             // prof.startCollecting();
             // long t = System.currentTimeMillis();
@@ -394,10 +394,10 @@ public class TestBtreeMapStore extends TestBase {
     private void testBtreeStore() {
         String fileName = getBaseDir() + "/testBtreeStore.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = openStore(fileName);
+        MVStore s = openStore(fileName);
         s.close();
         s = openStore(fileName);
-        BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
+        MVMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
         int count = 2000;
         // Profiler p = new Profiler();
         // p.startCollecting();
@@ -443,8 +443,8 @@ public class TestBtreeMapStore extends TestBase {
         FileUtils.delete(fileName);
         long initialLength = 0;
         for (int j = 0; j < 20; j++) {
-            BtreeMapStore s = openStore(fileName);
-            BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
+            MVStore s = openStore(fileName);
+            MVMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
             for (int i = 0; i < 10; i++) {
                 m.put(j + i, "Hello " + j);
             }
@@ -461,8 +461,8 @@ public class TestBtreeMapStore extends TestBase {
         }
         // long len = FileUtils.size(fileName);
         // System.out.println("len0: " + len);
-        BtreeMapStore s = openStore(fileName);
-        BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
+        MVStore s = openStore(fileName);
+        MVMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
         for (int i = 0; i < 100; i++) {
             m.remove(i);
         }
@@ -484,8 +484,8 @@ public class TestBtreeMapStore extends TestBase {
         FileUtils.delete(fileName);
         long initialLength = 0;
         for (int j = 0; j < 20; j++) {
-            BtreeMapStore s = openStore(fileName);
-            BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
+            MVStore s = openStore(fileName);
+            MVMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
             for (int i = 0; i < 10; i++) {
                 m.put(i, "Hello");
             }
@@ -508,8 +508,8 @@ public class TestBtreeMapStore extends TestBase {
     private void testRandom() {
         String fileName = getBaseDir() + "/testRandom.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = openStore(fileName);
-        BtreeMap<Integer, Integer> m = s.openMap("data", Integer.class, Integer.class);
+        MVStore s = openStore(fileName);
+        MVMap<Integer, Integer> m = s.openMap("data", Integer.class, Integer.class);
         TreeMap<Integer, Integer> map = new TreeMap<Integer, Integer>();
         Random r = new Random(1);
         int operationCount = 1000;
@@ -560,14 +560,14 @@ public class TestBtreeMapStore extends TestBase {
     private void testKeyValueClasses() {
         String fileName = getBaseDir() + "/testKeyValueClasses.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = openStore(fileName);
-        BtreeMap<Integer, String> is = s.openMap("intString", Integer.class, String.class);
+        MVStore s = openStore(fileName);
+        MVMap<Integer, String> is = s.openMap("intString", Integer.class, String.class);
         is.put(1, "Hello");
-        BtreeMap<Integer, Integer> ii = s.openMap("intInt", Integer.class, Integer.class);
+        MVMap<Integer, Integer> ii = s.openMap("intInt", Integer.class, Integer.class);
         ii.put(1, 10);
-        BtreeMap<String, Integer> si = s.openMap("stringInt", String.class, Integer.class);
+        MVMap<String, Integer> si = s.openMap("stringInt", String.class, Integer.class);
         si.put("Test", 10);
-        BtreeMap<String, String> ss = s.openMap("stringString", String.class, String.class);
+        MVMap<String, String> ss = s.openMap("stringString", String.class, String.class);
         ss.put("Hello", "World");
         try {
             s.openMap("invalid", Null.class, Integer.class);
@@ -598,8 +598,8 @@ public class TestBtreeMapStore extends TestBase {
     private void testIterate() {
         String fileName = getBaseDir() + "/testIterate.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = openStore(fileName);
-        BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
+        MVStore s = openStore(fileName);
+        MVMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
         Iterator<Integer> it = m.keyIterator(null);
         assertFalse(it.hasNext());
         for (int i = 0; i < 10; i++) {
@@ -631,8 +631,8 @@ public class TestBtreeMapStore extends TestBase {
     private void testSimple() {
         String fileName = getBaseDir() + "/testSimple.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = openStore(fileName);
-        BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
+        MVStore s = openStore(fileName);
+        MVMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
         for (int i = 0; i < 3; i++) {
             m.put(i, "hello " + i);
         }
@@ -655,8 +655,8 @@ public class TestBtreeMapStore extends TestBase {
         s.close();
     }
 
-    protected static BtreeMapStore openStore(String fileName) {
-        BtreeMapStore store = BtreeMapStore.open(fileName, new TestMapFactory());
+    protected static MVStore openStore(String fileName) {
+        MVStore store = MVStore.open(fileName, new TestMapFactory());
         store.setMaxPageSize(10);
         return store;
     }

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

@@ -5,8 +5,8 @@
  */
 package org.h2.test.store;
 
-import org.h2.dev.store.btree.BtreeMap;
-import org.h2.dev.store.btree.BtreeMapStore;
+import org.h2.dev.store.btree.MVMap;
+import org.h2.dev.store.btree.MVStore;
 import org.h2.dev.store.btree.DataType;
 import org.h2.dev.store.btree.MapFactory;
 import org.h2.dev.store.btree.StringType;
@@ -17,7 +17,7 @@ import org.h2.dev.store.btree.StringType;
 public class TestMapFactory implements MapFactory {
 
     @Override
-    public <K, V> BtreeMap<K, V> buildMap(String mapType, BtreeMapStore store,
+    public <K, V> MVMap<K, V> buildMap(String mapType, MVStore store,
             int id, String name, DataType keyType, DataType valueType,
             long createVersion) {
         if (mapType.equals("s")) {

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

@@ -14,7 +14,7 @@ import java.util.Random;
 import javax.imageio.ImageIO;
 import javax.imageio.ImageWriter;
 import javax.imageio.stream.FileImageOutputStream;
-import org.h2.dev.store.btree.BtreeMapStore;
+import org.h2.dev.store.btree.MVStore;
 import org.h2.store.fs.FileUtils;
 import org.h2.test.TestBase;
 import org.h2.util.New;
@@ -22,7 +22,7 @@ import org.h2.util.New;
 /**
  * Tests the r-tree.
  */
-public class TestRtree extends TestBtreeMapStore {
+public class TestRtree extends TestMVStore {
 
     /**
      * Run just this test.
@@ -43,7 +43,7 @@ public class TestRtree extends TestBtreeMapStore {
     private void testRtreeMany() {
         String fileName = getBaseDir() + "/testRtree.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s;
+        MVStore s;
         s = openStore(fileName);
         // s.setMaxPageSize(50);
         RtreeMap<SpatialKey, String> r = s.openMap("data", "r", "s2", "");
@@ -106,7 +106,7 @@ public class TestRtree extends TestBtreeMapStore {
     private void testRtree() {
         String fileName = getBaseDir() + "/testRtree.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s;
+        MVStore s;
         s = openStore(fileName);
         RtreeMap<SpatialKey, String> r = s.openMap("data", "r", "s2", "");
         add(r, "Bern", 46.57, 7.27, 124381);
@@ -198,7 +198,7 @@ public class TestRtree extends TestBtreeMapStore {
     private void testRandomRtree() {
         String fileName = getBaseDir() + "/testRtreeRandom.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = openStore(fileName);
+        MVStore s = openStore(fileName);
         RtreeMap<SpatialKey, String> m = s.openMap("data", "r", "s2", "");
         HashMap<SpatialKey, String> map = new HashMap<SpatialKey, String>();
         Random rand = new Random(1);
@@ -240,7 +240,7 @@ public class TestRtree extends TestBtreeMapStore {
     private void testCustomMapType() {
         String fileName = getBaseDir() + "/testMapType.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s;
+        MVStore s;
         s = openStore(fileName);
         SequenceMap<Integer, String> seq = s.openMap("data", "s", "i", "");
         StringBuilder buff = new StringBuilder();

h2/src/tools/org/h2/dev/store/btree/ChangeCursor.java

@@ -16,7 +16,7 @@ public class ChangeCursor<K, V> extends Cursor<K, V> {
 
     private final long minVersion;
 
-    ChangeCursor(BtreeMap<K, V> map, long minVersion) {
+    ChangeCursor(MVMap<K, V> map, long minVersion) {
         super(map);
         this.minVersion = minVersion;
     }

h2/src/tools/org/h2/dev/store/btree/Cursor.java

@@ -17,12 +17,12 @@ import java.util.Iterator;
  */
 public class Cursor<K, V> implements Iterator<K> {
 
-    protected final BtreeMap<K, V> map;
+    protected final MVMap<K, V> map;
     protected final ArrayList<CursorPos> parents = new ArrayList<CursorPos>();
     protected CursorPos currentPos;
     protected K current;
 
-    Cursor(BtreeMap<K, V> map) {
+    Cursor(MVMap<K, V> map) {
         this.map = map;
     }
 

h2/src/tools/org/h2/dev/store/btree/BtreeMap.java → h2/src/tools/org/h2/dev/store/btree/MVMap.java

@@ -17,9 +17,9 @@ import java.util.TreeMap;
  * @param <K> the key class
  * @param <V> the value class
  */
-public class BtreeMap<K, V> {
+public class MVMap<K, V> {
 
-    protected final BtreeMapStore store;
+    protected final MVStore store;
     protected Page root;
 
     private final int id;
@@ -36,7 +36,7 @@ public class BtreeMap<K, V> {
     private boolean closed;
     private boolean readOnly;
 
-    protected BtreeMap(BtreeMapStore store, int id, String name,
+    protected MVMap(MVStore store, int id, String name,
             DataType keyType, DataType valueType, long createVersion) {
         this.store = store;
         this.id = id;
@@ -469,19 +469,19 @@ public class BtreeMap<K, V> {
 
             @Override
             public Iterator<K> iterator() {
-                Cursor<K, V> c = new Cursor<K, V>(BtreeMap.this);
+                Cursor<K, V> c = new Cursor<K, V>(MVMap.this);
                 c.start(root, null);
                 return c;
             }
 
             @Override
             public int size() {
-                return BtreeMap.this.size();
+                return MVMap.this.size();
             }
 
             @Override
             public boolean contains(Object o) {
-                return BtreeMap.this.containsKey(o);
+                return MVMap.this.containsKey(o);
             }
 
         };
@@ -505,7 +505,7 @@ public class BtreeMap<K, V> {
         return name;
     }
 
-    BtreeMapStore getStore() {
+    MVStore getStore() {
         return store;
     }
 
@@ -597,7 +597,7 @@ public class BtreeMap<K, V> {
         store.removePage(p.getPos());
     }
 
-    public BtreeMap<K, V> openVersion(long version) {
+    public MVMap<K, V> openVersion(long version) {
         if (version < createVersion) {
             throw new IllegalArgumentException("Unknown version");
         }
@@ -605,7 +605,7 @@ public class BtreeMap<K, V> {
             return store.openMapVersion(version, name);
         }
         Page root = oldRoots.get(version);
-        BtreeMap<K, V> m = new BtreeMap<K, V>(store, id, name, keyType, valueType, createVersion);
+        MVMap<K, V> m = new MVMap<K, V>(store, id, name, keyType, valueType, createVersion);
         m.readOnly = true;
         m.root = root;
         return m;

h2/src/tools/org/h2/dev/store/btree/BtreeMapStore.java → h2/src/tools/org/h2/dev/store/btree/MVStore.java

@@ -39,7 +39,6 @@ blockSize=4096
 
 TODO:
 - implement complete java.util.Map interface
-- maybe rename to MVStore, MVMap, TestMVStore
 - limited support for writing to old versions (branches)
 - atomic test-and-set (when supporting concurrent writes)
 - support background writes (store old version)
@@ -63,7 +62,7 @@ TODO:
 /**
  * A persistent storage for tree maps.
  */
-public class BtreeMapStore {
+public class MVStore {
 
     public static final boolean ASSERT = false;
 
@@ -92,13 +91,13 @@ public class BtreeMapStore {
      */
     private HashMap<Long, HashMap<Integer, Chunk>> freedChunks = New.hashMap();
 
-    private BtreeMap<String, String> meta;
-    private HashMap<String, BtreeMap<?, ?>> maps = New.hashMap();
+    private MVMap<String, String> meta;
+    private HashMap<String, MVMap<?, ?>> maps = New.hashMap();
 
     /**
      * The set of maps with potentially unsaved changes.
      */
-    private HashMap<Integer, BtreeMap<?, ?>> mapsChanged = New.hashMap();
+    private HashMap<Integer, MVMap<?, ?>> mapsChanged = New.hashMap();
     private int lastMapId;
 
     private boolean reuseSpace = true;
@@ -110,7 +109,7 @@ public class BtreeMapStore {
     private int readCount;
     private int writeCount;
 
-    private BtreeMapStore(String fileName, MapFactory mapFactory) {
+    private MVStore(String fileName, MapFactory mapFactory) {
         this.fileName = fileName;
         this.mapFactory = mapFactory;
     }
@@ -121,7 +120,7 @@ public class BtreeMapStore {
      * @param fileName the file name
      * @return the store
      */
-    public static BtreeMapStore open(String fileName) {
+    public static MVStore open(String fileName) {
         return open(fileName, null);
     }
 
@@ -132,16 +131,16 @@ public class BtreeMapStore {
      * @param mapFactory the map factory
      * @return the store
      */
-    public static BtreeMapStore open(String fileName, MapFactory mapFactory) {
-        BtreeMapStore s = new BtreeMapStore(fileName, mapFactory);
+    public static MVStore open(String fileName, MapFactory mapFactory) {
+        MVStore s = new MVStore(fileName, mapFactory);
         s.open();
         return s;
     }
 
     @SuppressWarnings("unchecked")
-    <T extends BtreeMap<?, ?>> T  openMapVersion(long version, String name) {
+    <T extends MVMap<?, ?>> T  openMapVersion(long version, String name) {
         // TODO reduce copy & pasted source code
-        BtreeMap<String, String> oldMeta = getMetaMap(version);
+        MVMap<String, String> oldMeta = getMetaMap(version);
         String types = oldMeta.get("map." + name);
         String[] idTypeList = StringUtils.arraySplit(types, '/', false);
         int id = Integer.parseInt(idTypeList[0]);
@@ -151,7 +150,7 @@ public class BtreeMapStore {
         String valueType = idTypeList[4];
         String r = oldMeta.get("root." + id);
         long root = r == null ? 0 : Long.parseLong(r);
-        BtreeMap<?, ?> m = buildMap(mapType, id, name, keyType, valueType, createVersion);
+        MVMap<?, ?> m = buildMap(mapType, id, name, keyType, valueType, createVersion);
         m.setRootPos(root);
         return (T) m;
     }
@@ -167,8 +166,8 @@ public class BtreeMapStore {
      * @return the map
      */
     @SuppressWarnings("unchecked")
-    public <T extends BtreeMap<?, ?>> T openMap(String name, String mapType, String keyType, String valueType) {
-        BtreeMap<?, ?> m = maps.get(name);
+    public <T extends MVMap<?, ?>> T openMap(String name, String mapType, String keyType, String valueType) {
+        MVMap<?, ?> m = maps.get(name);
         if (m == null) {
             String identifier = meta.get("map." + name);
             int id;
@@ -198,11 +197,11 @@ public class BtreeMapStore {
         return (T) m;
     }
 
-    private BtreeMap<?, ?> buildMap(String mapType, int id, String name, String keyType, String valueType, long createVersion) {
+    private MVMap<?, ?> buildMap(String mapType, int id, String name, String keyType, String valueType, long createVersion) {
         DataType k = buildDataType(keyType);
         DataType v = buildDataType(valueType);
         if (mapType.equals("")) {
-            return new BtreeMap<Object, Object>(this, id, name, k, v, createVersion);
+            return new MVMap<Object, Object>(this, id, name, k, v, createVersion);
         }
         return getMapFactory().buildMap(mapType, this, id, name, k, v, createVersion);
     }
@@ -218,18 +217,18 @@ public class BtreeMapStore {
      *
      * @return the metadata map
      */
-    public BtreeMap<String, String> getMetaMap() {
+    public MVMap<String, String> getMetaMap() {
         return meta;
     }
 
-    private BtreeMap<String, String> getMetaMap(long version) {
+    private MVMap<String, String> getMetaMap(long version) {
         Chunk c = getChunkForVersion(version);
         if (c == null) {
             throw new IllegalArgumentException("Unknown version: " + version);
         }
         // TODO avoid duplicate code
         c = readChunkHeader(c.start);
-        BtreeMap<String, String> oldMeta = new BtreeMap<String, String>(this, 0, "old-meta", STRING_TYPE, STRING_TYPE, 0);
+        MVMap<String, String> oldMeta = new MVMap<String, String>(this, 0, "old-meta", STRING_TYPE, STRING_TYPE, 0);
         oldMeta.setRootPos(c.metaRootPos);
         return oldMeta;
     }
@@ -255,16 +254,16 @@ public class BtreeMapStore {
      * @param valueClass the value class
      * @return the map
      */
-    public <K, V> BtreeMap<K, V> openMap(String name, Class<K> keyClass, Class<V> valueClass) {
+    public <K, V> MVMap<K, V> openMap(String name, Class<K> keyClass, Class<V> valueClass) {
         String keyType = getDataType(keyClass);
         String valueType = getDataType(valueClass);
         @SuppressWarnings("unchecked")
-        BtreeMap<K, V> m = (BtreeMap<K, V>) openMap(name, "", keyType, valueType);
+        MVMap<K, V> m = (MVMap<K, V>) openMap(name, "", keyType, valueType);
         return m;
     }
 
     void removeMap(String name) {
-        BtreeMap<?, ?> m = maps.remove(name);
+        MVMap<?, ?> m = maps.remove(name);
         mapsChanged.remove(m);
     }
 
@@ -294,12 +293,12 @@ public class BtreeMapStore {
      *
      * @param map the map
      */
-    void markChanged(BtreeMap<?, ?> map) {
+    void markChanged(MVMap<?, ?> map) {
         mapsChanged.put(map.getId(), map);
     }
 
     private void open() {
-        meta = new BtreeMap<String, String>(this, 0, "meta", STRING_TYPE, STRING_TYPE, 0);
+        meta = new MVMap<String, String>(this, 0, "meta", STRING_TYPE, STRING_TYPE, 0);
         if (fileName == null) {
             return;
         }
@@ -391,7 +390,7 @@ public class BtreeMapStore {
             try {
                 log("file close");
                 file.close();
-                for (BtreeMap<?, ?> m : New.arrayList(maps.values())) {
+                for (MVMap<?, ?> m : New.arrayList(maps.values())) {
                     m.close();
                 }
                 meta = null;
@@ -473,7 +472,7 @@ public class BtreeMapStore {
         }
         int count = 0;
         int maxLength = 1 + 4 + 4 + 8;
-        for (BtreeMap<?, ?> m : mapsChanged.values()) {
+        for (MVMap<?, ?> m : mapsChanged.values()) {
             if (m == meta || !m.hasUnsavedChanges()) {
                 continue;
             }
@@ -495,7 +494,7 @@ public class BtreeMapStore {
         buff.putInt(0);
         buff.putInt(0);
         buff.putLong(0);
-        for (BtreeMap<?, ?> m : mapsChanged.values()) {
+        for (MVMap<?, ?> m : mapsChanged.values()) {
             if (m == meta || !m.hasUnsavedChanges()) {
                 continue;
             }
@@ -627,7 +626,7 @@ public class BtreeMapStore {
         if (mapsChanged.size() == 0) {
             return false;
         }
-        for (BtreeMap<?, ?> m : mapsChanged.values()) {
+        for (MVMap<?, ?> m : mapsChanged.values()) {
             if (m.hasUnsavedChanges()) {
                 return true;
             }
@@ -755,7 +754,7 @@ public class BtreeMapStore {
         // to ensure a chunk will be written
         // (even if there is nothing to move)
         meta.put("chunk." + move.id, move.toString());
-        BtreeMap<String, String> oldMeta = new BtreeMap<String, String>(this, 0, "old-meta", STRING_TYPE, STRING_TYPE, 0);
+        MVMap<String, String> oldMeta = new MVMap<String, String>(this, 0, "old-meta", STRING_TYPE, STRING_TYPE, 0);
         oldMeta.setRootPos(move.metaRootPos);
         Iterator<String> it = oldMeta.keyIterator("map.");
         while (it.hasNext()) {
@@ -766,7 +765,7 @@ public class BtreeMapStore {
             String s = oldMeta.get(k);
             k = k.substring("map.".length());
             @SuppressWarnings("unchecked")
-            BtreeMap<Object, Object> data = (BtreeMap<Object, Object>) maps.get(k);
+            MVMap<Object, Object> data = (MVMap<Object, Object>) maps.get(k);
             if (data == null) {
                 continue;
             }
@@ -777,7 +776,7 @@ public class BtreeMapStore {
             DataType vt = buildDataType(idTypeList[4]);
             long oldDataRoot = Long.parseLong(oldMeta.get("root." + id));
             if (oldDataRoot != 0) {
-                BtreeMap<?, ?> oldData = new BtreeMap<Object, Object>(this, id, "old-" + k, kt, vt, 0);
+                MVMap<?, ?> oldData = new MVMap<Object, Object>(this, id, "old-" + k, kt, vt, 0);
                 oldData.setRootPos(oldDataRoot);
                 Iterator<?> dataIt = oldData.keyIterator(null);
                 while (dataIt.hasNext()) {
@@ -812,7 +811,7 @@ public class BtreeMapStore {
      * @param pos the page position
      * @return the page
      */
-    Page readPage(BtreeMap<?, ?> map, long pos) {
+    Page readPage(MVMap<?, ?> map, long pos) {
         Page p = cache.get(pos);
         if (p == null) {
             long filePos = getFilePosition(pos);
@@ -926,7 +925,7 @@ public class BtreeMapStore {
         }
         // also, all check referenced by this version
         // need to be available in the file
-        BtreeMap<String, String> oldMeta = getMetaMap(version);
+        MVMap<String, String> oldMeta = getMetaMap(version);
         if (oldMeta == null) {
             return false;
         }
@@ -954,7 +953,7 @@ public class BtreeMapStore {
             throw new IllegalArgumentException("Unknown version: " + version);
         }
         // TODO could remove newer temporary pages on rollback
-        for (BtreeMap<?, ?> m : mapsChanged.values()) {
+        for (MVMap<?, ?> m : mapsChanged.values()) {
             m.rollbackTo(version);
         }
         for (long v = currentVersion; v >= version; v--) {
@@ -983,7 +982,7 @@ public class BtreeMapStore {
                 readMeta();
             }
         }
-        for (BtreeMap<?, ?> m : maps.values()) {
+        for (MVMap<?, ?> m : maps.values()) {
             if (m.getCreateVersion() > version) {
                 m.close();
                 removeMap(m.getName());
@@ -1000,7 +999,7 @@ public class BtreeMapStore {
 
     private void revertTemp() {
         freedChunks.clear();
-        for (BtreeMap<?, ?> m : mapsChanged.values()) {
+        for (MVMap<?, ?> m : mapsChanged.values()) {
             m.revertTemp();
         }
         mapsChanged.clear();

h2/src/tools/org/h2/dev/store/btree/MapFactory.java

@@ -23,8 +23,8 @@ public interface MapFactory {
      * @param createVersion when the map was created
      * @return the map
      */
-     <K, V> BtreeMap<K, V> buildMap(
-             String mapType, BtreeMapStore store, int id, String name,
+     <K, V> MVMap<K, V> buildMap(
+             String mapType, MVStore store, int id, String name,
              DataType keyType, DataType valueType, long createVersion);
 
     /**

h2/src/tools/org/h2/dev/store/btree/Page.java

@@ -27,7 +27,7 @@ public class Page {
 
     private static final int SHARED_KEYS = 1, SHARED_VALUES = 2, SHARED_CHILDREN = 4, SHARED_COUNTS = 8;
 
-    private final BtreeMap<?, ?> map;
+    private final MVMap<?, ?> map;
     private final long version;
     private long pos;
     private long totalCount;
@@ -49,7 +49,7 @@ public class Page {
     private Page[] childrenPages;
     private long[] counts;
 
-    private Page(BtreeMap<?, ?> map, long version) {
+    private Page(MVMap<?, ?> map, long version) {
         this.map = map;
         this.version = version;
     }
@@ -64,7 +64,7 @@ public class Page {
      * @param children the children
      * @return the page
      */
-    public static Page create(BtreeMap<?, ?> map, long version,
+    public static Page create(MVMap<?, ?> map, long version,
             int keyCount, Object[] keys,
             Object[] values, long[] children, Page[] childrenPages, long[] counts,
             long totalCount, int sharedFlags) {
@@ -89,7 +89,7 @@ public class Page {
      * @param buff the source buffer
      * @return the page
      */
-    static Page read(FileChannel file, BtreeMap<?, ?> map,
+    static Page read(FileChannel file, MVMap<?, ?> map,
             long filePos, long pos) {
         int maxLength = DataUtils.getPageMaxLength(pos), length = maxLength;
         ByteBuffer buff;
@@ -300,7 +300,7 @@ public class Page {
     }
 
     public long getTotalCount() {
-        if (BtreeMapStore.ASSERT) {
+        if (MVStore.ASSERT) {
             long check = 0;
             if (isLeaf()) {
                 check = keyCount;