A persistent tree map (work in progress).

h2/src/tools/org/h2/dev/store/btree/IntegerType.java → h2/src/test/org/h2/test/store/IntegerType.java

@@ -4,9 +4,11 @@
  * (http://h2database.com/html/license.html).
  * Initial Developer: H2 Group
  */
-package org.h2.dev.store.btree;
+package org.h2.test.store;
 
 import java.nio.ByteBuffer;
+import org.h2.dev.store.btree.DataType;
+import org.h2.dev.store.btree.DataUtils;
 
 /**
  * An integer type.
@@ -21,6 +23,14 @@ class IntegerType implements DataType {
         return DataUtils.getVarIntLen((Integer) obj);
     }
 
+    public int getMaxLength(Object obj) {
+        return DataUtils.MAX_VAR_INT_LEN;
+    }
+
+    public int getMemory(Object obj) {
+        return 20;
+    }
+
     public Integer read(ByteBuffer buff) {
         return DataUtils.readVarInt(buff);
     }

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

+/*
+ * Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
+ * Version 1.0, and under the Eclipse Public License, Version 1.0
+ * (http://h2database.com/html/license.html).
+ * Initial Developer: H2 Group
+ */
+package org.h2.test.store;
+
+import java.nio.ByteBuffer;
+import org.h2.dev.store.btree.DataType;
+import org.h2.dev.store.btree.DataTypeFactory;
+import org.h2.dev.store.btree.DataUtils;
+import org.h2.util.StringUtils;
+
+/**
+ * A row type.
+ */
+public class RowType implements DataType {
+
+    private final DataType[] types;
+
+    private RowType(DataType[] types) {
+        this.types = types;
+    }
+
+    public int compare(Object a, Object b) {
+        if (a == b) {
+            return 0;
+        }
+        Object[] ax = (Object[]) a;
+        Object[] bx = (Object[]) b;
+        int al = ax.length;
+        int bl = bx.length;
+        int len = Math.min(al, bl);
+        for (int i = 0; i < len; i++) {
+            int comp = types[i].compare(ax[i], bx[i]);
+            if (comp != 0) {
+                return comp;
+            }
+        }
+        if (len < al) {
+            return -1;
+        } else if (len < bl) {
+            return 1;
+        }
+        return 0;
+    }
+
+    public int length(Object obj) {
+        Object[] x = (Object[]) obj;
+        int len = x.length;
+        int result = DataUtils.getVarIntLen(len);
+        for (int i = 0; i < len; i++) {
+            result += types[i].length(x[i]);
+        }
+        return result;
+    }
+
+    public int getMaxLength(Object obj) {
+        Object[] x = (Object[]) obj;
+        int len = x.length;
+        int result = DataUtils.MAX_VAR_INT_LEN;
+        for (int i = 0; i < len; i++) {
+            result += types[i].getMaxLength(x[i]);
+        }
+        return result;
+    }
+
+    public int getMemory(Object obj) {
+        Object[] x = (Object[]) obj;
+        int len = x.length;
+        int memory = 0;
+        for (int i = 0; i < len; i++) {
+            memory += types[i].getMemory(x[i]);
+        }
+        return memory;
+    }
+
+    public Object[] read(ByteBuffer buff) {
+        int len = DataUtils.readVarInt(buff);
+        Object[] x = new Object[len];
+        for (int i = 0; i < len; i++) {
+            x[i] = types[i].read(buff);
+        }
+        return x;
+    }
+
+    public void write(ByteBuffer buff, Object obj) {
+        Object[] x = (Object[]) obj;
+        int len = x.length;
+        DataUtils.writeVarInt(buff, len);
+        for (int i = 0; i < len; i++) {
+            types[i].write(buff, x[i]);
+        }
+    }
+
+    public String asString() {
+        StringBuilder buff = new StringBuilder();
+        buff.append('r');
+        buff.append('(');
+        for (int i = 0; i < types.length; i++) {
+            if (i > 0) {
+                buff.append(',');
+            }
+            buff.append(types[i].asString());
+        }
+        buff.append(')');
+        return buff.toString();
+    }
+
+    static RowType fromString(String t, DataTypeFactory factory) {
+        if (!t.startsWith("r(") || !t.endsWith(")")) {
+            throw new RuntimeException("Unknown type: " + t);
+        }
+        t = t.substring(2, t.length() - 1);
+        String[] array = StringUtils.arraySplit(t, ',', false);
+        DataType[] types = new DataType[array.length];
+        for (int i = 0; i < array.length; i++) {
+            types[i] = factory.fromString(array[i]);
+        }
+        return new RowType(types);
+    }
+
+}

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

@@ -29,6 +29,7 @@ public class TestTreeMapStore extends TestBase {
     }
 
     public void test() throws Exception {
+        testLargeImport();
         testBtreeStore();
         testDefragment();
         testReuseSpace();
@@ -38,10 +39,39 @@ public class TestTreeMapStore extends TestBase {
         testSimple();
     }
 
+    private void testLargeImport() throws Exception {
+        String fileName = getBaseDir() + "/testCsv.h3";
+        int len = 10000;
+        for (int j = 0; j < 5; j++) {
+            FileUtils.delete(fileName);
+            BtreeMapStore s = openStore(fileName);
+            s.setMaxPageSize(40);
+            RowType rowType = RowType.fromString("r(i,,)", new TestTypeFactory());
+            BtreeMap<Integer, Object[]> m = s.openMap("data", new IntegerType(), rowType);
+            int i = 0;
+            // long t = System.currentTimeMillis();
+            for (; i < len;) {
+              Object[] o = new Object[3];
+              o[0] = i;
+              o[1] = "Hello";
+              o[2] = "World";
+              m.put(i, o);
+              i++;
+              if (i % 10000 == 0) {
+                  s.store();
+              }
+            }
+            s.store();
+            s.close();
+            // System.out.println("store time " + (System.currentTimeMillis() - t));
+            // System.out.println("store size " + FileUtils.size(fileName));
+        }
+    }
+
     private void testBtreeStore() {
         String fileName = getBaseDir() + "/testBtreeStore.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = BtreeMapStore.open(fileName);
+        BtreeMapStore s = openStore(fileName);
         BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
         int count = 2000;
         // Profiler p = new Profiler();
@@ -64,8 +94,9 @@ public class TestTreeMapStore extends TestBase {
         for (int i = 1; i < count; i++) {
             assertEquals("hello " + i, m.get(i));
         }
+        s.store();
         s.close();
-        s = BtreeMapStore.open(fileName);
+        s = openStore(fileName);
         m = s.openMap("data", Integer.class, String.class);
         assertNull(m.get(0));
         for (int i = 1; i < count; i++) {
@@ -87,7 +118,7 @@ public class TestTreeMapStore extends TestBase {
         FileUtils.delete(fileName);
         long initialLength = 0;
         for (int j = 0; j < 20; j++) {
-            BtreeMapStore s = BtreeMapStore.open(fileName);
+            BtreeMapStore s = openStore(fileName);
             BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
             for (int i = 0; i < 10; i++) {
                 m.put(j + i, "Hello " + j);
@@ -103,9 +134,9 @@ public class TestTreeMapStore extends TestBase {
                 assertTrue("initial: " + initialLength + " len: " + len, len <= initialLength * 3);
             }
         }
-        long len = FileUtils.size(fileName);
+        // long len = FileUtils.size(fileName);
         // System.out.println("len0: " + len);
-        BtreeMapStore s = BtreeMapStore.open(fileName);
+        BtreeMapStore s = openStore(fileName);
         BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
         for (int i = 0; i < 100; i++) {
             m.remove(i);
@@ -113,13 +144,13 @@ public class TestTreeMapStore extends TestBase {
         s.store();
         s.compact();
         s.close();
-        len = FileUtils.size(fileName);
+        // len = FileUtils.size(fileName);
         // System.out.println("len1: " + len);
-        s = BtreeMapStore.open(fileName);
+        s = openStore(fileName);
         m = s.openMap("data", Integer.class, String.class);
         s.compact();
         s.close();
-        len = FileUtils.size(fileName);
+        // len = FileUtils.size(fileName);
         // System.out.println("len2: " + len);
     }
 
@@ -127,14 +158,15 @@ public class TestTreeMapStore extends TestBase {
         String fileName = getBaseDir() + "/testReuseSpace.h3";
         FileUtils.delete(fileName);
         long initialLength = 0;
-        for (int j = 0; j < 10; j++) {
-            BtreeMapStore s = BtreeMapStore.open(fileName);
+        for (int j = 0; j < 20; j++) {
+            BtreeMapStore s = openStore(fileName);
             BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
             for (int i = 0; i < 10; i++) {
                 m.put(i, "Hello");
             }
             s.store();
             for (int i = 0; i < 10; i++) {
+                assertEquals("Hello", m.get(i));
                 m.remove(i);
             }
             s.store();
@@ -151,23 +183,25 @@ public class TestTreeMapStore extends TestBase {
     private void testRandom() {
         String fileName = getBaseDir() + "/testRandom.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = BtreeMapStore.open(fileName);
+        BtreeMapStore s = openStore(fileName);
         BtreeMap<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;
-        int maxValue = 20;
+        int operationCount = 10000;
+        int maxValue = 30;
         for (int i = 0; i < operationCount; i++) {
             int k = r.nextInt(maxValue);
             int v = r.nextInt();
             boolean compareAll;
             switch (r.nextInt(3)) {
             case 0:
+                log(i + ": put " + k + " = " + v);
                 m.put(k, v);
                 map.put(k, v);
                 compareAll = true;
                 break;
             case 1:
+                log(i + ": remove " + k);
                 m.remove(k);
                 map.remove(k);
                 compareAll = true;
@@ -185,10 +219,12 @@ public class TestTreeMapStore extends TestBase {
             }
             if (compareAll) {
                 Iterator<Integer> it = m.keyIterator(null);
-                Iterator<Integer> it2 = map.keySet().iterator();
-                while (it2.hasNext()) {
+                Iterator<Integer> itExpected = map.keySet().iterator();
+                while (itExpected.hasNext()) {
                     assertTrue(it.hasNext());
-                    assertEquals(it2.next(), it.next());
+                    Integer expected = itExpected.next();
+                    Integer got = it.next();
+                    assertEquals(expected, got);
                 }
                 assertFalse(it.hasNext());
             }
@@ -199,7 +235,7 @@ public class TestTreeMapStore extends TestBase {
     private void testKeyValueClasses() {
         String fileName = getBaseDir() + "/testKeyValueClasses.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = BtreeMapStore.open(fileName);
+        BtreeMapStore s = openStore(fileName);
         BtreeMap<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);
@@ -220,8 +256,9 @@ public class TestTreeMapStore extends TestBase {
         } catch (RuntimeException e) {
             // expected
         }
+        s.store();
         s.close();
-        s = BtreeMapStore.open(fileName);
+        s = openStore(fileName);
         is = s.openMap("intString", Integer.class, String.class);
         assertEquals("Hello", is.get(1));
         ii = s.openMap("intInt", Integer.class, Integer.class);
@@ -236,7 +273,7 @@ public class TestTreeMapStore extends TestBase {
     private void testIterate() {
         String fileName = getBaseDir() + "/testIterate.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = BtreeMapStore.open(fileName);
+        BtreeMapStore s = openStore(fileName);
         BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
         Iterator<Integer> it = m.keyIterator(null);
         assertFalse(it.hasNext());
@@ -269,7 +306,7 @@ public class TestTreeMapStore extends TestBase {
     private void testSimple() {
         String fileName = getBaseDir() + "/testSimple.h3";
         FileUtils.delete(fileName);
-        BtreeMapStore s = BtreeMapStore.open(fileName);
+        BtreeMapStore s = openStore(fileName);
         BtreeMap<Integer, String> m = s.openMap("data", Integer.class, String.class);
         for (int i = 0; i < 3; i++) {
             m.put(i, "hello " + i);
@@ -281,10 +318,10 @@ public class TestTreeMapStore extends TestBase {
         for (int i = 1; i < 3; i++) {
             assertEquals("hello " + i, m.get(i));
         }
-
+        s.store();
         s.close();
 
-        s = BtreeMapStore.open(fileName);
+        s = openStore(fileName);
         m = s.openMap("data", Integer.class, String.class);
         assertNull(m.get(0));
         for (int i = 1; i < 3; i++) {
@@ -293,4 +330,19 @@ public class TestTreeMapStore extends TestBase {
         s.close();
     }
 
+    private static BtreeMapStore openStore(String fileName) {
+        BtreeMapStore store = BtreeMapStore.open(fileName, new TestTypeFactory());
+        store.setMaxPageSize(10);
+        return store;
+    }
+
+    /**
+     * Log the message.
+     *
+     * @param msg the message
+     */
+    private static void log(String msg) {
+        // System.out.println(msg);
+    }
+
 }

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

+/*
+ * Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License, Version
+ * 1.0, and under the Eclipse Public License, Version 1.0
+ * (http://h2database.com/html/license.html). Initial Developer: H2 Group
+ */
+package org.h2.test.store;
+
+import org.h2.dev.store.btree.DataType;
+import org.h2.dev.store.btree.DataTypeFactory;
+import org.h2.dev.store.btree.StringType;
+
+/**
+ * A data type factory.
+ */
+public class TestTypeFactory implements DataTypeFactory {
+
+    public DataType fromString(String s) {
+        if (s.length() == 0) {
+            return new StringType();
+        }
+        switch (s.charAt(0)) {
+        case 'i':
+            return new IntegerType();
+        case 'r':
+            return RowType.fromString(s, this);
+        }
+        throw new RuntimeException("Unknown data type " + s);
+    }
+
+    public DataType getDataType(Class<?> objectClass) {
+        if (objectClass == Integer.class) {
+            return new IntegerType();
+        }
+        throw new RuntimeException("Unsupported object class " + objectClass.toString());
+    }
+
+}

h2/src/test/org/h2/test/store/package.html

+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<!--
+Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License, Version 1.0,
+and under the Eclipse Public License, Version 1.0
+(http://h2database.com/html/license.html).
+Initial Developer: H2 Group
+-->
+<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
+<head><meta http-equiv="Content-Type" content="text/html;charset=utf-8" /><title>
+Javadoc package documentation
+</title></head><body style="font: 9pt/130% Tahoma, Arial, Helvetica, sans-serif; font-weight: normal;"><p>
+
+This package contains tests for the map store.
+
+</p></body></html>
\ No newline at end of file

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

@@ -17,13 +17,15 @@ import java.util.Iterator;
 public class BtreeMap<K, V> {
 
     private final BtreeMapStore store;
+    private final long id;
     private final String name;
     private final DataType keyType;
     private final DataType valueType;
     private Page root;
 
-    private BtreeMap(BtreeMapStore store, String name, DataType keyType, DataType valueType) {
+    private BtreeMap(BtreeMapStore store, long id, String name, DataType keyType, DataType valueType) {
         this.store = store;
+        this.id = id;
         this.name = name;
         this.keyType = keyType;
         this.valueType = valueType;
@@ -40,8 +42,8 @@ public class BtreeMap<K, V> {
      * @param valueClass the value class
      * @return the map
      */
-    static <K, V> BtreeMap<K, V> open(BtreeMapStore store, String name, DataType keyType, DataType valueType) {
-        return new BtreeMap<K, V>(store, name, keyType, valueType);
+    static <K, V> BtreeMap<K, V> open(BtreeMapStore store, long id, String name, DataType keyType, DataType valueType) {
+        return new BtreeMap<K, V>(store, id, name, keyType, valueType);
     }
 
     /**
@@ -51,9 +53,7 @@ public class BtreeMap<K, V> {
      * @param data the value
      */
     public void put(K key, V data) {
-        if (!isChanged()) {
-            store.markChanged(name, this);
-        }
+        markChanged();
         root = Page.put(this, root, key, data);
     }
 
@@ -77,23 +77,32 @@ public class BtreeMap<K, V> {
      * @param key the key
      * @return the value, or null if not found
      */
-    public Page getPage(K key) {
+    Page getPage(K key) {
         if (root == null) {
             return null;
         }
         return root.findPage(key);
     }
 
+    /**
+     * Remove all entries.
+     */
+    public void clear() {
+        if (root != null) {
+            markChanged();
+            root.removeAllRecursive();
+            root = null;
+        }
+    }
+
     /**
      * Remove a key-value pair.
      *
      * @param key the key
      */
     public void remove(K key) {
-        if (!isChanged()) {
-            store.markChanged(name, this);
-        }
         if (root != null) {
+            markChanged();
             root = Page.remove(root, key);
         }
     }
@@ -107,6 +116,12 @@ public class BtreeMap<K, V> {
         return root != null && root.getId() < 0;
     }
 
+    private void markChanged() {
+        if (!isChanged()) {
+            store.markChanged(name, this);
+        }
+    }
+
     /**
      * Compare two keys.
      *
@@ -206,4 +221,12 @@ public class BtreeMap<K, V> {
         return name;
     }
 
+    int getMaxPageSize() {
+        return store.getMaxPageSize();
+    }
+
+    long getId() {
+        return id;
+    }
+
 }

h2/src/tools/org/h2/dev/store/btree/Block.java → h2/src/tools/org/h2/dev/store/btree/Chunk.java

@@ -11,12 +11,12 @@ import java.io.IOException;
 import java.util.Properties;
 
 /**
- * A block of data.
+ * A chunk of data, containing one or multiple pages
  */
-class Block {
+class Chunk {
 
     /**
-     * The block id.
+     * The chunk id.
      */
     int id;
 
@@ -26,7 +26,7 @@ class Block {
     long start;
 
     /**
-     * The length in bytes.
+     * The length in bytes (may be larger than the actual value).
      */
     long length;
 
@@ -45,7 +45,12 @@ class Block {
      */
     int collectPriority;
 
-    Block(int id) {
+    /**
+     * The offset of the meta root.
+     */
+    int metaRootOffset;
+
+    Chunk(int id) {
         this.id = id;
     }
 
@@ -55,17 +60,18 @@ class Block {
      * @param s the string
      * @return the block
      */
-    static Block fromString(String s) {
-        Block b = new Block(0);
+    static Chunk fromString(String s) {
+        Chunk c = new Chunk(0);
         Properties prop = new Properties();
         try {
             prop.load(new ByteArrayInputStream(s.getBytes("UTF-8")));
-            b.id = Integer.parseInt(prop.get("id").toString());
-            b.start = Long.parseLong(prop.get("start").toString());
-            b.length = Long.parseLong(prop.get("length").toString());
-            b.entryCount = Integer.parseInt(prop.get("entryCount").toString());
-            b.liveCount = Integer.parseInt(prop.get("liveCount").toString());
-            return b;
+            c.id = Integer.parseInt(prop.get("id").toString());
+            c.start = Long.parseLong(prop.get("start").toString());
+            c.length = Long.parseLong(prop.get("length").toString());
+            c.entryCount = Integer.parseInt(prop.get("entryCount").toString());
+            c.liveCount = Integer.parseInt(prop.get("liveCount").toString());
+            c.metaRootOffset = Integer.parseInt(prop.get("metaRoot").toString());
+            return c;
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
@@ -80,7 +86,7 @@ class Block {
     }
 
     public boolean equals(Object o) {
-        return o instanceof Block && ((Block) o).id == id;
+        return o instanceof Chunk && ((Chunk) o).id == id;
     }
 
     public String toString() {
@@ -89,7 +95,8 @@ class Block {
             "start:" + start + "\n" +
             "length:" + length + "\n" +
             "entryCount:" + entryCount + "\n" +
-            "liveCount:" + liveCount + "\n";
+            "liveCount:" + liveCount + "\n" +
+            "metaRoot:" + metaRootOffset + "\n";
     }
 
 }

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

@@ -11,8 +11,11 @@ import java.util.Iterator;
 
 /**
  * A cursor to iterate over elements in ascending order.
+ *
+ * @param <K> the key type
  */
 class Cursor<K> implements Iterator<K> {
+
     private ArrayList<CursorPos> parents = new ArrayList<CursorPos>();
     private K current;
 

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

@@ -23,20 +23,37 @@ public interface DataType {
     int compare(Object a, Object b);
 
     /**
-     * Get the length in bytes.
+     * Get the length in bytes used to store an object.
      *
      * @param obj the object
      * @return the length
      */
     int length(Object obj);
 
+    /**
+     * Get the maximum length in bytes used to store an object. In many cases,
+     * this method can be faster than calculating the exact length.
+     *
+     * @param obj the object
+     * @return the maximum length
+     */
+    int getMaxLength(Object obj);
+
+    /**
+     * Estimate the used memory in bytes.
+     *
+     * @param obj the object
+     * @return the used memory
+     */
+    int getMemory(Object obj);
+
     /**
      * Write the object.
      *
      * @param buff the target buffer
      * @param x the value
      */
-    void write(ByteBuffer buff, Object x);
+    void write(ByteBuffer buff, Object obj);
 
     /**
      * Read an object.

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

@@ -6,34 +6,18 @@
  */
 package org.h2.dev.store.btree;
 
-import java.io.IOException;
-import java.io.StringReader;
-
 /**
  * A factory for data types.
  */
-public class DataTypeFactory {
+public interface DataTypeFactory {
 
     /**
      * Read the data type.
      *
-     * @param buff the buffer
+     * @param s the string
      * @return the type
      */
-    static DataType fromString(String s) {
-        StringReader r = new StringReader(s);
-        char c;
-        try {
-            c = (char) r.read();
-        } catch (IOException e) {
-            throw new RuntimeException(e);
-        }
-        switch (c) {
-        case 'i':
-            return new IntegerType();
-        }
-        throw new RuntimeException("Unknown data type " + c);
-    }
+    DataType fromString(String s);
 
     /**
      * Get the data type object for the given class.
@@ -41,13 +25,6 @@ public class DataTypeFactory {
      * @param objectClass the class
      * @return the data type object
      */
-    static DataType getDataType(Class<?> objectClass) {
-        if (objectClass == Integer.class) {
-            return new IntegerType();
-        } else if (objectClass == String.class) {
-            return new StringType();
-        }
-        throw new RuntimeException("Unsupported object class " + objectClass.toString());
-    }
+    DataType getDataType(Class<?> objectClass);
 
 }

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

@@ -13,13 +13,18 @@ import java.nio.ByteBuffer;
  */
 public class DataUtils {
 
+    /**
+     * The maximum length of a variable size int.
+     */
+    public static final int MAX_VAR_INT_LEN = 5;
+
     /**
      * Get the length of the variable size int.
      *
      * @param x the value
      * @return the length in bytes
      */
-    static int getVarIntLen(int x) {
+    public static int getVarIntLen(int x) {
         if ((x & (-1 << 7)) == 0) {
             return 1;
         } else if ((x & (-1 << 14)) == 0) {
@@ -55,7 +60,7 @@ public class DataUtils {
      * @param buff the source buffer
      * @return the value
      */
-    static int readVarInt(ByteBuffer buff) {
+    public static int readVarInt(ByteBuffer buff) {
         int b = buff.get();
         if (b >= 0) {
             return b;
@@ -111,7 +116,7 @@ public class DataUtils {
      * @param buff the target buffer
      * @param x the value
      */
-    static void writeVarInt(ByteBuffer buff, int x) {
+    public static void writeVarInt(ByteBuffer buff, int x) {
         while ((x & ~0x7f) != 0) {
             buff.put((byte) (0x80 | (x & 0x7f)));
             x >>>= 7;
@@ -133,4 +138,22 @@ public class DataUtils {
         buff.put((byte) x);
     }
 
+    static void copyWithGap(Object src, Object dst, int oldSize, int gapIndex) {
+        if (gapIndex > 0) {
+            System.arraycopy(src, 0, dst, 0, gapIndex);
+        }
+        if (gapIndex < oldSize) {
+            System.arraycopy(src, gapIndex, dst, gapIndex + 1, oldSize - gapIndex);
+        }
+    }
+
+    static void copyExcept(Object src, Object dst, int oldSize, int removeIndex) {
+        if (removeIndex > 0 && oldSize > 0) {
+            System.arraycopy(src, 0, dst, 0, removeIndex);
+        }
+        if (removeIndex < oldSize) {
+            System.arraycopy(src, removeIndex + 1, dst, removeIndex, oldSize - removeIndex - 1);
+        }
+    }
+
 }

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

+/*
+ * Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
+ * Version 1.0, and under the Eclipse Public License, Version 1.0
+ * (http://h2database.com/html/license.html).
+ * Initial Developer: H2 Group
+ */
+package org.h2.dev.store.btree;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.StringReader;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.util.Arrays;
+import java.util.Properties;
+import org.h2.store.fs.FilePath;
+import org.h2.store.fs.FileUtils;
+
+/**
+ * Convert a database file to a human-readable text dump.
+ */
+public class Dump {
+
+    private static int blockSize = 4 * 1024;
+
+    public static void main(String... args) {
+        String fileName = "test.h3";
+        for (int i = 0; i < args.length; i++) {
+            if ("-file".equals(args[i])) {
+                fileName = args[++i];
+            }
+        }
+        dump(fileName);
+    }
+
+    public static void dump(String fileName) {
+        if (!FileUtils.exists(fileName)) {
+            System.out.println("File not found: " + fileName);
+            return;
+        }
+        FileChannel file = null;
+        try {
+            file = FilePath.get(fileName).open("r");
+            long fileLength = file.size();
+            file.position(0);
+            byte[] header = new byte[blockSize];
+            file.read(ByteBuffer.wrap(header));
+            Properties prop = new Properties();
+            prop.load(new ByteArrayInputStream(header));
+            prop.load(new StringReader(new String(header, "UTF-8")));
+            System.out.println("file " + fileName);
+            System.out.println("    length " + fileLength);
+            System.out.println("    " + prop);
+            ByteBuffer block = ByteBuffer.wrap(new byte[16]);
+            for (long pos = 0; pos < fileLength;) {
+                file.position(pos);
+                block.rewind();
+                FileUtils.readFully(file,  block);
+                block.rewind();
+                if (block.get() != 'c') {
+                    pos += blockSize;
+                    continue;
+                }
+                int length = block.getInt();
+                int chunkId = block.getInt();
+                int metaRootOffset = block.getInt();
+                System.out.println("    chunk " + chunkId + " at " + pos +
+                        " length " + length + " offset " + metaRootOffset);
+                ByteBuffer chunk = ByteBuffer.allocate(length);
+                file.position(pos);
+                FileUtils.readFully(file, chunk);
+                int p = block.position();
+                pos = (pos + length + blockSize) / blockSize * blockSize;
+                length -= p;
+                while (length > 0) {
+                    chunk.position(p);
+                    int len = chunk.getInt();
+                    long mapId = chunk.getLong();
+                    int type = chunk.get();
+                    int count = DataUtils.readVarInt(chunk);
+                    if (type == 1) {
+                        long[] children = new long[count];
+                        for (int i = 0; i < count; i++) {
+                            children[i] = chunk.getLong();
+                        }
+                        System.out.println("        map " + mapId + " at " + p + " node, " + count + " children: " + Arrays.toString(children));
+                    } else {
+                        System.out.println("        map " + mapId + " at " + p + " leaf, " + count + " rows");
+                    }
+                    p += len;
+                    length -= len;
+                }
+            }
+        } catch (IOException e) {
+            System.out.println("ERROR: " + e);
+        } finally {
+            try {
+                file.close();
+            } catch (IOException e) {
+                // ignore
+            }
+        }
+        System.out.println();
+    }
+
+}

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

@@ -11,39 +11,67 @@ import java.nio.ByteBuffer;
 /**
  * A string type.
  */
-class StringType implements DataType {
+public class StringType implements DataType {
 
     public int compare(Object a, Object b) {
         return a.toString().compareTo(b.toString());
     }
 
     public int length(Object obj) {
-        try {
-            byte[] bytes = obj.toString().getBytes("UTF-8");
-            return DataUtils.getVarIntLen(bytes.length) + bytes.length;
-        } catch (Exception e) {
-            throw new RuntimeException(e);
+        int plus = 0;
+        String s = obj.toString();
+        int len = s.length();
+        for (int i = 0; i < len; i++) {
+            char c = s.charAt(i);
+            if (c >= 0x800) {
+                plus += 2;
+            } else if (c >= 0x80) {
+                plus++;
+            }
         }
+        return DataUtils.getVarIntLen(len) + len + plus;
+    }
+
+    public int getMaxLength(Object obj) {
+        return DataUtils.MAX_VAR_INT_LEN + obj.toString().length() * 3;
+    }
+
+    public int getMemory(Object obj) {
+        return obj.toString().length() * 2 + 48;
     }
 
     public String read(ByteBuffer buff) {
         int len = DataUtils.readVarInt(buff);
-        byte[] bytes = new byte[len];
-        buff.get(bytes);
-        try {
-            return new String(bytes, "UTF-8");
-        } catch (Exception e) {
-            throw new RuntimeException(e);
+        char[] chars = new char[len];
+        for (int i = 0; i < len; i++) {
+            int x = buff.get() & 0xff;
+            if (x < 0x80) {
+                chars[i] = (char) x;
+            } else if (x >= 0xe0) {
+                chars[i] = (char) (((x & 0xf) << 12) + ((buff.get() & 0x3f) << 6) + (buff.get() & 0x3f));
+            } else {
+                chars[i] = (char) (((x & 0x1f) << 6) + (buff.get() & 0x3f));
+            }
         }
+        return new String(chars);
     }
 
-    public void write(ByteBuffer buff, Object x) {
-        try {
-            byte[] bytes = x.toString().getBytes("UTF-8");
-            DataUtils.writeVarInt(buff, bytes.length);
-            buff.put(bytes);
-        } catch (Exception e) {
-            throw new RuntimeException(e);
+    public void write(ByteBuffer buff, Object obj) {
+        String s = obj.toString();
+        int len = s.length();
+        DataUtils.writeVarInt(buff, len);
+        for (int i = 0; i < len; i++) {
+            int c = s.charAt(i);
+            if (c < 0x80) {
+                buff.put((byte) c);
+            } else if (c >= 0x800) {
+                buff.put((byte) (0xe0 | (c >> 12)));
+                buff.put((byte) (((c >> 6) & 0x3f)));
+                buff.put((byte) (c & 0x3f));
+            } else {
+                buff.put((byte) (0xc0 | (c >> 6)));
+                buff.put((byte) (c & 0x3f));
+            }
         }
     }
 

h2/src/tools/org/h2/dev/store/tree/StoredMap.java

@@ -132,7 +132,7 @@ public class StoredMap<K, V> {
     /**
      * A value type.
      */
-    static interface ValueType {
+    interface ValueType {
 
         /**
          * Get the length in bytes.
@@ -170,7 +170,7 @@ public class StoredMap<K, V> {
     /**
      * A key type.
      */
-    static interface KeyType extends ValueType {
+    interface KeyType extends ValueType {
 
         /**
          * Compare two keys.