Skip to content

H
h2database
提交 44a16bd2 authored 作者: Thomas Mueller's avatar Thomas Mueller
浏览文件
操作

Sharded map (work in progress)

上级 251063bc
显示空白字符变更
内嵌 并排
正在显示 包含 417 行增加 和 0 行删除
h2/src/test/org/h2/test/store/TestShardedMap.java 0 → 100644
浏览文件 @ 44a16bd2
/*
* Copyright 2004-2013 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.util.TreeMap;
import org.h2.dev.cluster.ShardedMap;
import org.h2.test.TestBase;
/**
* Test sharded maps.
*/
public class TestShardedMap extends TestBase {
/**
* Run just this test.
*
* @param a ignored
*/
public static void main(String... a) throws Exception {
TestBase.createCaller().init().test();
}
@Override
public void test() {
testLinearSplit();
testReplication();
testOverlap();
}
private void testLinearSplit() {
ShardedMap<Integer, Integer> map = new ShardedMap<Integer, Integer>();
TreeMap<Integer, Integer> a = new TreeMap<Integer, Integer>();
TreeMap<Integer, Integer> b = new TreeMap<Integer, Integer>();
map.addMap(a, null, 5);
map.addMap(b, 5, null);
for (int i = 0; i < 10; i++) {
map.put(i, i * 10);
}
assertEquals(10, map.size());
for (int i = 0; i < 10; i++) {
assertEquals(i * 10, map.get(i).intValue());
}
assertEquals("[0, 1, 2, 3, 4]",
a.keySet().toString());
assertEquals("[5, 6, 7, 8, 9]",
b.keySet().toString());
assertEquals("[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]",
map.keySet().toString());
assertEquals(10, map.sizeAsLong());
}
private void testReplication() {
ShardedMap<Integer, Integer> map = new ShardedMap<Integer, Integer>();
TreeMap<Integer, Integer> a = new TreeMap<Integer, Integer>();
TreeMap<Integer, Integer> b = new TreeMap<Integer, Integer>();
map.addMap(a, null, null);
map.addMap(b, null, null);
for (int i = 0; i < 10; i++) {
map.put(i, i * 10);
}
assertEquals(10, map.size());
for (int i = 0; i < 10; i++) {
assertEquals(i * 10, map.get(i).intValue());
}
assertEquals("[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]",
a.keySet().toString());
assertEquals("[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]",
b.keySet().toString());
assertEquals("[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]",
map.keySet().toString());
assertEquals(10, map.sizeAsLong());
}
private void testOverlap() {
ShardedMap<Integer, Integer> map = new ShardedMap<Integer, Integer>();
TreeMap<Integer, Integer> a = new TreeMap<Integer, Integer>();
TreeMap<Integer, Integer> b = new TreeMap<Integer, Integer>();
map.addMap(a, null, 10);
map.addMap(b, 5, null);
for (int i = 0; i < 20; i++) {
map.put(i, i * 10);
}
// overlap: size is unknown
assertEquals(-1, map.size());
for (int i = 0; i < 20; i++) {
assertEquals(i * 10, map.get(i).intValue());
}
assertEquals("[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]",
a.keySet().toString());
assertEquals("[5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]",
b.keySet().toString());
assertEquals(-1, map.sizeAsLong());
}
}
\ No newline at end of file
h2/src/tools/org/h2/dev/cluster/ShardedMap.java 0 → 100644
浏览文件 @ 44a16bd2
/*
* Copyright 2004-2013 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.cluster;
import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import org.h2.mvstore.DataUtils;
import org.h2.mvstore.type.DataType;
import org.h2.mvstore.type.ObjectDataType;
/**
* A sharded map. It is typically split into multiple sub-maps that don't have
* overlapping keys.
*
* @param <K> the key type
* @param <V> the value type
*/
public class ShardedMap<K, V> extends AbstractMap<K, V>
implements Map<K, V> {
private final DataType keyType;
/**
* The shards. Each shard has a minimum and a maximum key (null for no
* limit). Key ranges are ascending but can overlap, in which case entries
* may be stored in multiple maps. If that is the case, for read operations,
* the entry in the first map is used, and for write operations, the changes
* are applied to all maps within the range.
*/
private Shard<K, V>[] shards;
public ShardedMap() {
this(new ObjectDataType());
}
@SuppressWarnings("unchecked")
public ShardedMap(DataType keyType) {
this.keyType = keyType;
shards = new Shard[0];
}
public static long getSize(Map<?, ?> map) {
if (map instanceof LargeMap) {
return ((LargeMap) map).sizeAsLong();
}
return map.size();
}
/**
* Add the given shard.
*
* @param map the map
* @param min the lowest key, or null if no limit
* @param max the highest key, or null if no limit
*/
public void addMap(Map<K, V> map, K min, K max) {
if (min != null && max != null && keyType.compare(min, max) > 0) {
DataUtils.newIllegalArgumentException("Invalid range: {0} .. {1}", min, max);
}
int len = shards.length + 1;
Shard<K, V>[] newShards = Arrays.copyOf(shards, len);
Shard<K, V> newShard = new Shard<K, V>();
newShard.map = map;
newShard.minIncluding = min;
newShard.maxExcluding = max;
newShards[len - 1] = newShard;
shards = newShards;
}
private boolean isInRange(K key, Shard<K, V> shard) {
if (shard.minIncluding != null) {
if (keyType.compare(key, shard.minIncluding) < 0) {
return false;
}
}
if (shard.maxExcluding != null) {
if (keyType.compare(key, shard.maxExcluding) >= 0) {
return false;
}
}
return true;
}
@Override
public int size() {
long size = sizeAsLong();
return size > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) size;
}
public long sizeAsLong() {
Shard<K, V>[] copy = shards;
for (Shard<K, V> s : copy) {
if (s.minIncluding == null && s.maxExcluding == null) {
return getSize(s.map);
}
}
if (isSimpleSplit(copy)) {
long size = 0;
for (Shard<K, V> s : copy) {
size += getSize(s.map);
}
return size;
}
return -1;
}
private boolean isSimpleSplit(Shard<K, V>[] shards) {
K last = null;
for (int i = 0; i < shards.length; i++) {
Shard<K, V> s = shards[i];
if (last == null) {
if (s.minIncluding != null) {
return false;
}
} else if (keyType.compare(last, s.minIncluding) != 0) {
return false;
}
if (s.maxExcluding == null) {
return i == shards.length - 1;
}
last = s.maxExcluding;
}
return last == null;
}
@Override
public V put(K key, V value) {
V result = null;
Shard<K, V>[] copy = shards;
for (Shard<K, V> s : copy) {
if (isInRange(key, s)) {
V r = s.map.put(key, value);
if (result == null) {
result = r;
}
}
}
return result;
}
@Override
public V get(Object key) {
@SuppressWarnings("unchecked")
K k = (K) key;
Shard<K, V>[] copy = shards;
for (Shard<K, V> s : copy) {
if (isInRange(k, s)) {
return s.map.get(k);
}
}
return null;
}
@Override
public Set<Entry<K, V>> entrySet() {
Shard<K, V>[] copy = shards;
for (Shard<K, V> s : copy) {
if (s.minIncluding == null && s.maxExcluding == null) {
return s.map.entrySet();
}
}
if (isSimpleSplit(copy)) {
return new CombinedSet<K, V>(size(), copy);
}
return null;
}
/**
* A subset of a map.
*
* @param <K> the key type
* @param <V> the value type
*/
static class Shard<K, V> {
/**
* The lowest key, or null if no limit.
*/
K minIncluding;
/**
* A key higher than the highest key, or null if no limit.
*/
K maxExcluding;
/**
* The backing map.
*/
Map<K, V> map;
@Override
public String toString() {
StringBuilder buff = new StringBuilder();
if (minIncluding != null) {
buff.append('[').append(minIncluding);
}
buff.append("..");
if (maxExcluding != null) {
buff.append(maxExcluding).append(')');
}
return buff.toString();
}
}
/**
* A combination of multiple sets.
*
* @param <K> the key type
* @param <V> the value type
*/
private static class CombinedSet<K, V> extends AbstractSet<Entry<K, V>> {
final int size;
final Shard<K, V>[] shards;
CombinedSet(int size, Shard<K, V>[] shards) {
this.size = size;
this.shards = shards;
}
@Override
public Iterator<Entry<K, V>> iterator() {
return new Iterator<Entry<K, V>>() {
boolean init;
Entry<K, V> current;
Iterator<Entry<K, V>> currentIterator;
int shardIndex;
private void fetchNext() {
while (currentIterator == null || !currentIterator.hasNext()) {
if (shardIndex >= shards.length) {
current = null;
return;
}
currentIterator = shards[shardIndex++].map.entrySet().iterator();
}
current = currentIterator.next();
}
@Override
public boolean hasNext() {
if (!init) {
fetchNext();
init = true;
}
return current != null;
}
@Override
public Entry<K, V> next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
Entry<K, V> e = current;
fetchNext();
return e;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
@Override
public int size() {
return size;
}
}
/**
* A large map.
*/
public interface LargeMap {
long sizeAsLong();
}
/**
* A map that can efficiently return the index of a key, and the key at a
* given index.
*/
public interface CountedMap<K, V> {
K getKey(long index);
long getKeyIndex(K key);
}
}
h2/src/tools/org/h2/dev/cluster/package.html 0 → 100644
浏览文件 @ 44a16bd2
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!--
Copyright 2004-2013 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>
A clustering implementation.
</p></body></html>
\ No newline at end of file
Markdown 格式
0% 或
您添加了 0 人 到此讨论。请谨慎行事。
请先完成此评论的编辑！
请 注册 或者 后发表评论