remove mapId from TransactionMap, since it duplicates id from MVMap

remove maps registry from TransactionStore, because it duplicates MVStore's one

h2/src/main/org/h2/mvstore/tx/Transaction.java

@@ -345,8 +345,7 @@ public class Transaction {
      */
     public <K, V> TransactionMap<K, V> openMap(MVMap<K, VersionedValue> map) {
         checkNotClosed();
-        int mapId = map.getId();
-        return new TransactionMap<>(this, map, mapId);
+        return new TransactionMap<>(this, map);
     }
 
     /**

h2/src/main/org/h2/mvstore/tx/TransactionMap.java

@@ -24,11 +24,6 @@ import java.util.Map;
  */
 public class TransactionMap<K, V> {
 
-    /**
-     * The map id.
-     */
-    final int mapId;
-
     /**
      * If a record was read that was updated by this transaction, and the
      * update occurred before this log id, the older version is read. This
@@ -50,11 +45,9 @@ public class TransactionMap<K, V> {
      */
     final Transaction transaction;
 
-    TransactionMap(Transaction transaction, MVMap<K, VersionedValue> map,
-                    int mapId) {
+    TransactionMap(Transaction transaction, MVMap<K, VersionedValue> map) {
         this.transaction = transaction;
         this.map = map;
-        this.mapId = mapId;
     }
 
     /**
@@ -77,7 +70,7 @@ public class TransactionMap<K, V> {
     public TransactionMap<K, V> getInstance(Transaction transaction,
                                             long savepoint) {
         TransactionMap<K, V> m =
-                new TransactionMap<>(transaction, map, mapId);
+                new TransactionMap<>(transaction, map);
         m.setSavepoint(savepoint);
         return m;
     }
@@ -141,7 +134,7 @@ public class TransactionMap<K, V> {
                 cursor.next();
                 Object[] op = cursor.getValue();
                 int m = (int) op[0];
-                if (m != mapId) {
+                if (m != map.getId()) {
                     // a different map - ignore
                     continue;
                 }

h2/src/main/org/h2/mvstore/tx/TransactionStore.java

@@ -8,7 +8,6 @@ package org.h2.mvstore.tx;
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.BitSet;
-import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
@@ -53,12 +52,6 @@ public class TransactionStore {
      */
     final MVMap<Long, Object[]> undoLog;
 
-    /**
-     * The map of maps.
-     */
-    private final HashMap<Integer, MVMap<Object, VersionedValue>> maps =
-            new HashMap<>();
-
     private final DataType dataType;
 
     /**
@@ -408,7 +401,6 @@ public class TransactionStore {
      * @param map the map
      */
     synchronized <K, V> void removeMap(TransactionMap<K, V> map) {
-        maps.remove(map.mapId);
         store.removeMap(map.map);
     }
 
@@ -476,7 +468,7 @@ public class TransactionStore {
      * @param valueType the value type
      * @return the map
      */
-    synchronized <K> MVMap<K, VersionedValue> openMap(String name,
+    <K> MVMap<K, VersionedValue> openMap(String name,
             DataType keyType, DataType valueType) {
         if (keyType == null) {
             keyType = new ObjectDataType();
@@ -490,9 +482,6 @@ public class TransactionStore {
                 new MVMap.Builder<K, VersionedValue>().
                 keyType(keyType).valueType(vt);
         map = store.openMap(name, builder);
-        @SuppressWarnings("unchecked")
-        MVMap<Object, VersionedValue> m = (MVMap<Object, VersionedValue>) map;
-        maps.put(map.getId(), m);
         return map;
     }
 
@@ -502,22 +491,20 @@ public class TransactionStore {
      * @param mapId the id
      * @return the map
      */
-    synchronized MVMap<Object, VersionedValue> openMap(int mapId) {
-        MVMap<Object, VersionedValue> map = maps.get(mapId);
-        if (map != null) {
-            return map;
-        }
-        String mapName = store.getMapName(mapId);
-        if (mapName == null) {
-            // the map was removed later on
-            return null;
+    MVMap<Object, VersionedValue> openMap(int mapId) {
+        MVMap<Object, VersionedValue> map = store.getMap(mapId);
+        if (map == null) {
+            String mapName = store.getMapName(mapId);
+            if (mapName == null) {
+                // the map was removed later on
+                return null;
+            }
+            DataType vt = new VersionedValue.Type(dataType);
+            MVMap.Builder<Object, VersionedValue> mapBuilder =
+                    new MVMap.Builder<Object, VersionedValue>().
+                    keyType(dataType).valueType(vt);
+            map = store.openMap(mapName, mapBuilder);
         }
-        DataType vt = new VersionedValue.Type(dataType);
-        MVMap.Builder<Object, VersionedValue> mapBuilder =
-                new MVMap.Builder<Object, VersionedValue>().
-                keyType(dataType).valueType(vt);
-        map = store.openMap(mapName, mapBuilder);
-        maps.put(mapId, map);
         return map;
     }