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提交 ecf54428 authored 作者: Thomas Mueller's avatar Thomas Mueller
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A persistent multi-version map (work in progress)

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h2/src/tools/org/h2/dev/store/btree/BtreeMap.java
浏览文件 @ ecf54428
......@@ -19,11 +19,6 @@ import java.util.TreeMap;
*/
public class BtreeMap<K, V> {
protected static final IllegalArgumentException KEY_NOT_FOUND = new IllegalArgumentException(
"Key not found");
protected static final IllegalArgumentException KEY_ALREADY_EXISTS = new IllegalArgumentException(
"Key already exists");
protected Page root;
protected BtreeMapStore store;
......@@ -59,76 +54,32 @@ public class BtreeMap<K, V> {
public void put(K key, V data) {
checkWrite();
Page oldRoot = root;
if (containsKey(key)) {
root = set(root, store.getCurrentVersion(), key, data);
} else {
root = add(root, store.getCurrentVersion(), key, data);
}
root = put(oldRoot, store.getCurrentVersion(), key, data, store.getMaxPageSize());
markChanged(oldRoot);
}
/**
* Update a value for an existing key.
*
* @param map the map
* @param p the page (may not be null)
* @param writeVersion the write version
* @param key the key
* @param value the value
* @return the root page
* @throws InvalidArgumentException if this key does not exist (without
* stack trace)
*/
protected Page set(Page p, long writeVersion, Object key, Object value) {
if (p == null) {
throw KEY_NOT_FOUND;
}
int index = p.binarySearch(key);
if (p.isLeaf()) {
if (index < 0) {
throw KEY_NOT_FOUND;
}
p = p.copyOnWrite(writeVersion);
p.setValue(index, value);
return p;
}
// it is a node
if (index < 0) {
index = -index - 1;
} else {
index++;
}
Page c = p.getChildPage(index);
Page c2 = set(c, writeVersion, key, value);
if (c != c2) {
p = p.copyOnWrite(writeVersion);
p.setChild(index, c2);
}
return p;
}
/**
* Add a new key-value pair.
* Add or update a key-value pair.
*
* @param map the map
* @param p the page (may be null)
* @param writeVersion the write version
* @param key the key
* @param value the value
* @param value the value (may not be null)
* @param maxPageSize the maximum page size
* @return the root page
* @throws InvalidArgumentException if this key already exists (without
* stack trace)
*/
protected Page add(Page p, long writeVersion, Object key, Object value) {
protected Page put(Page p, long writeVersion, Object key, Object value, int maxPageSize) {
if (p == null) {
Object[] keys = { key };
Object[] values = { value };
p = Page.create(this, writeVersion, keys, values, null, null, 1);
p = Page.create(this, writeVersion, 1,
keys, values, null, null, 1, 0);
return p;
}
if (p.getKeyCount() >= store.getMaxPageSize()) {
// only possible if this is the root,
// otherwise we would have split earlier
if (p.getKeyCount() > maxPageSize) {
// only possible if this is the root, else we would have split earlier
// (this requires maxPageSize is fixed)
p = p.copyOnWrite(writeVersion);
int at = p.getKeyCount() / 2;
long totalSize = p.getTotalSize();
......@@ -137,17 +88,18 @@ public class BtreeMap<K, V> {
Object[] keys = { k };
long[] children = { p.getPos(), split.getPos() };
long[] childrenSize = { p.getTotalSize(), split.getTotalSize() };
p = Page.create(this, writeVersion, keys, null, children, childrenSize,
totalSize);
p = Page.create(this, writeVersion, 1,
keys, null, children, childrenSize, totalSize, 0);
// now p is a node; insert continues
} else if (p.isLeaf()) {
int index = p.binarySearch(key);
if (index >= 0) {
throw KEY_ALREADY_EXISTS;
}
index = -index - 1;
p = p.copyOnWrite(writeVersion);
p.insert(index, key, value, 0, 0);
if (index < 0) {
index = -index - 1;
p.insertLeaf(index, key, value);
} else {
p.setValue(index, value);
}
return p;
}
// p is a node
......@@ -158,7 +110,7 @@ public class BtreeMap<K, V> {
index++;
}
Page c = p.getChildPage(index);
if (c.getKeyCount() >= store.getMaxPageSize()) {
if (c.getKeyCount() >= maxPageSize) {
// split on the way down
c = c.copyOnWrite(writeVersion);
int at = c.getKeyCount() / 2;
......@@ -166,14 +118,16 @@ public class BtreeMap<K, V> {
Page split = c.split(at);
p = p.copyOnWrite(writeVersion);
p.setChild(index, split);
p.insert(index, k, null, c.getPos(), c.getTotalSize());
p.insertNode(index, k, c.getPos(), c.getTotalSize());
// now we are not sure where to add
return add(p, writeVersion, key, value);
return put(p, writeVersion, key, value, maxPageSize);
}
Page c2 = add(c, writeVersion, key, value);
long oldSize = c.getTotalSize();
Page c2 = put(c, writeVersion, key, value, maxPageSize);
if (c != c2 || oldSize != c2.getTotalSize()) {
p = p.copyOnWrite(writeVersion);
// the child might be the same, but not the size
p.setChild(index, c2);
}
return p;
}
......@@ -364,26 +318,22 @@ public class BtreeMap<K, V> {
*/
public void remove(K key) {
checkWrite();
if (containsKey(key)) {
Page oldRoot = root;
root = removeExisting(root, store.getCurrentVersion(), key);
if (oldRoot != null) {
root = remove(oldRoot, store.getCurrentVersion(), key);
markChanged(oldRoot);
}
}
/**
* Remove an existing key-value pair.
* Remove a key-value pair.
*
* @param p the page (may not be null)
* @param writeVersion the write version
* @param key the key
* @return the new root page (null if empty)
* @throws InvalidArgumentException if not found (without stack trace)
*/
protected Page removeExisting(Page p, long writeVersion, Object key) {
if (p == null) {
throw KEY_NOT_FOUND;
}
protected Page remove(Page p, long writeVersion, Object key) {
int index = p.binarySearch(key);
if (p.isLeaf()) {
if (index >= 0) {
......@@ -393,8 +343,6 @@ public class BtreeMap<K, V> {
}
p = p.copyOnWrite(writeVersion);
p.remove(index);
} else {
throw KEY_NOT_FOUND;
}
return p;
}
......@@ -405,16 +353,18 @@ public class BtreeMap<K, V> {
index++;
}
Page c = p.getChildPage(index);
Page c2 = removeExisting(c, writeVersion, key);
p = p.copyOnWrite(writeVersion);
long oldSize = c.getTotalSize();
Page c2 = remove(c, writeVersion, key);
if (c2 == null) {
// this child was deleted
p = p.copyOnWrite(writeVersion);
p.remove(index);
if (p.getKeyCount() == 0) {
removePage(p);
p = p.getChildPage(0);
}
} else {
} else if (oldSize != c2.getTotalSize()) {
p = p.copyOnWrite(writeVersion);
p.setChild(index, c2);
}
return p;
......
h2/src/tools/org/h2/dev/store/btree/BtreeMapStore.java
浏览文件 @ ecf54428
......@@ -11,6 +11,7 @@ import java.io.StringReader;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.BitSet;
import java.util.Collections;
import java.util.Comparator;
......@@ -56,6 +57,7 @@ TODO:
- compare with newest version of IndexedDb
- support database version / schema version
- implement more counted b-tree (skip, get positions)
- merge pages if small
*/
......@@ -64,7 +66,7 @@ TODO:
*/
public class BtreeMapStore {
public static final boolean ASSERT = true;
public static final boolean ASSERT = false;
private static final StringType STRING_TYPE = new StringType();
......@@ -82,6 +84,7 @@ public class BtreeMapStore {
private int tempPageId;
private Map<Long, Page> cache = CacheLIRS.newInstance(readCacheSize, 2048);
private HashMap<Long, Page> temp = New.hashMap();
private Page[] tempCache = new Page[64];
private int lastChunkId;
private HashMap<Integer, Chunk> chunks = New.hashMap();
......@@ -367,6 +370,7 @@ public class BtreeMapStore {
m.close();
}
temp.clear();
Arrays.fill(tempCache, null);
meta = null;
compressor = null;
chunks.clear();
......@@ -598,9 +602,11 @@ public class BtreeMapStore {
* @return the page id
*/
long registerTempPage(Page p) {
long id = --tempPageId;
temp.put(id, p);
return id;
long pos = --tempPageId;
temp.put(pos, p);
int index = (int) pos & (tempCache.length - 1);
tempCache[index] = p;
return pos;
}
/**
......@@ -799,7 +805,13 @@ public class BtreeMapStore {
*/
Page readPage(BtreeMap<?, ?> map, long pos) {
if (pos < 0) {
return temp.get(pos);
int index = (int) pos & (tempCache.length - 1);
Page p = tempCache[index];
if (p == null || p.getPos() != pos) {
p = temp.get(pos);
tempCache[index] = p;
}
return p;
}
Page p = cache.get(pos);
if (p == null) {
......@@ -993,6 +1005,7 @@ public class BtreeMapStore {
}
mapsChanged.clear();
temp.clear();
Arrays.fill(tempCache, null);
tempPageId = 0;
}
......
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