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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;
}
......
h2/src/tools/org/h2/dev/store/btree/Page.java
浏览文件 @ ecf54428
......@@ -9,6 +9,7 @@ package org.h2.dev.store.btree;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.Arrays;
import org.h2.compress.Compressor;
/**
......@@ -24,15 +25,28 @@ import org.h2.compress.Compressor;
*/
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 long version;
private long pos;
private long totalCount;
private int keyCount;
/**
* The last result of a find operation is cached.
*/
private int cachedCompare;
/**
* Which arrays are shared with another version of this page.
*/
private int sharedFlags;
private Object[] keys;
private Object[] values;
private long[] children;
private long[] counts;
private int cachedCompare;
private long totalCount;
private Page(BtreeMap<?, ?> map, long version) {
this.map = map;
......@@ -49,16 +63,19 @@ public class Page {
* @param children the children
* @return the page
*/
public static Page create(BtreeMap<?, ?> map, long version, Object[] keys,
public static Page create(BtreeMap<?, ?> map, long version,
int keyCount, Object[] keys,
Object[] values, long[] children, long[] counts,
long totalCount) {
long totalCount, int sharedFlags) {
Page p = new Page(map, version);
p.pos = map.getStore().registerTempPage(p);
p.keys = keys;
p.keyCount = keyCount;
p.values = values;
p.children = children;
p.counts = counts;
p.totalCount = totalCount;
p.sharedFlags = sharedFlags;
return p;
}
......@@ -70,8 +87,8 @@ public class Page {
* @param buff the source buffer
* @return the page
*/
static Page read(FileChannel file, BtreeMap<?, ?> map, long filePos,
long pos) {
static Page read(FileChannel file, BtreeMap<?, ?> map,
long filePos, long pos) {
int maxLength = DataUtils.getPageMaxLength(pos), length = maxLength;
ByteBuffer buff;
try {
......@@ -108,7 +125,7 @@ public class Page {
}
public int getKeyCount() {
return keys.length;
return keyCount;
}
public boolean isLeaf() {
......@@ -127,14 +144,14 @@ public class Page {
public String toString() {
StringBuilder buff = new StringBuilder();
buff.append("pos: ").append(pos).append("\n");
for (int i = 0; i <= keys.length; i++) {
for (int i = 0; i <= keyCount; i++) {
if (i > 0) {
buff.append(" ");
}
if (children != null) {
buff.append("[" + children[i] + "] ");
}
if (i < keys.length) {
if (i < keyCount) {
buff.append(keys[i]);
if (values != null) {
buff.append(':');
......@@ -150,8 +167,10 @@ public class Page {
return this;
}
map.getStore().removePage(pos);
Page newPage = create(map, writeVersion, keys, values, children,
counts, totalCount);
Page newPage = create(map, writeVersion,
keyCount, keys, values, children,
counts, totalCount,
SHARED_KEYS | SHARED_VALUES | SHARED_CHILDREN | SHARED_COUNTS);
newPage.cachedCompare = cachedCompare;
return newPage;
}
......@@ -167,7 +186,7 @@ public class Page {
* @return the value or null
*/
public int binarySearch(Object key) {
int low = 0, high = keys.length - 1;
int low = 0, high = keyCount - 1;
int x = cachedCompare - 1;
if (x < 0 || x > high) {
x = (low + high) >>> 1;
......@@ -188,7 +207,7 @@ public class Page {
return -(low + 1);
// regular binary search (without caching)
// int low = 0, high = keys.length - 1;
// int low = 0, high = keyCount - 1;
// while (low <= high) {
// int x = (low + high) >>> 1;
// int compare = map.compare(key, keys[x]);
......@@ -208,31 +227,35 @@ public class Page {
}
private Page splitLeaf(int at) {
int a = at, b = keys.length - a;
int a = at, b = keyCount - a;
Object[] aKeys = new Object[a];
Object[] bKeys = new Object[b];
System.arraycopy(keys, 0, aKeys, 0, a);
System.arraycopy(keys, a, bKeys, 0, b);
keys = aKeys;
keyCount = a;
Object[] aValues = new Object[a];
Object[] bValues = new Object[b];
bValues = new Object[b];
System.arraycopy(values, 0, aValues, 0, a);
System.arraycopy(values, a, bValues, 0, b);
values = aValues;
totalCount = keys.length;
Page newPage = create(map, version, bKeys, bValues, null, null,
bKeys.length);
sharedFlags &= ~(SHARED_KEYS | SHARED_VALUES);
totalCount = a;
Page newPage = create(map, version, b,
bKeys, bValues, null, null,
bKeys.length, 0);
return newPage;
}
private Page splitNode(int at) {
int a = at, b = keys.length - a;
int a = at, b = keyCount - a;
Object[] aKeys = new Object[a];
Object[] bKeys = new Object[b - 1];
System.arraycopy(keys, 0, aKeys, 0, a);
System.arraycopy(keys, a + 1, bKeys, 0, b - 1);
keys = aKeys;
keyCount = a;
long[] aChildren = new long[a + 1];
long[] bChildren = new long[b];
System.arraycopy(children, 0, aChildren, 0, a + 1);
......@@ -243,6 +266,7 @@ public class Page {
System.arraycopy(counts, 0, aCounts, 0, a + 1);
System.arraycopy(counts, a + 1, bCounts, 0, b);
counts = aCounts;
sharedFlags &= ~(SHARED_KEYS | SHARED_CHILDREN | SHARED_COUNTS);
long t = 0;
for (long x : aCounts) {
t += x;
......@@ -252,8 +276,9 @@ public class Page {
for (long x : bCounts) {
t += x;
}
Page newPage = create(map, version, bKeys, null, bChildren,
bCounts, t);
Page newPage = create(map, version, b - 1,
bKeys, null, bChildren,
bCounts, t, 0);
return newPage;
}
......@@ -261,7 +286,7 @@ public class Page {
if (BtreeMapStore.ASSERT) {
long check = 0;
if (isLeaf()) {
check = keys.length;
check = keyCount;
} else {
for (long x : counts) {
check += x;
......@@ -277,37 +302,37 @@ public class Page {
public void setChild(int index, Page c) {
if (c.getPos() != children[index]) {
long[] newChildren = new long[children.length];
System.arraycopy(children, 0, newChildren, 0, newChildren.length);
newChildren[index] = c.getPos();
children = newChildren;
if ((sharedFlags & SHARED_CHILDREN) != 0) {
children = Arrays.copyOf(children, children.length);
sharedFlags &= ~SHARED_CHILDREN;
}
children[index] = c.getPos();
}
if (c.getTotalSize() != counts[index]) {
long[] newCounts = new long[counts.length];
System.arraycopy(counts, 0, newCounts, 0,
newCounts.length);
newCounts[index] = c.getTotalSize();
totalCount += newCounts[index] - counts[index];
counts = newCounts;
if ((sharedFlags & SHARED_COUNTS) != 0) {
counts = Arrays.copyOf(counts, counts.length);
sharedFlags &= ~SHARED_COUNTS;
}
long oldCount = counts[index];
counts[index] = c.getTotalSize();
totalCount += counts[index] - oldCount;
}
}
public void setKey(int index, Object key) {
// create a copy - not required if already cloned once in this version,
// but avoid unnecessary cloning would require a "modified" flag
Object[] newKeys = new Object[keys.length];
System.arraycopy(keys, 0, newKeys, 0, newKeys.length);
newKeys[index] = key;
keys = newKeys;
if ((sharedFlags & SHARED_KEYS) != 0) {
keys = Arrays.copyOf(keys, keys.length);
sharedFlags &= ~SHARED_KEYS;
}
keys[index] = key;
}
public void setValue(int index, Object value) {
// create a copy - not required if already cloned once in this version,
// but avoid unnecessary cloning would require a "modified" flag
Object[] newValues = new Object[values.length];
System.arraycopy(values, 0, newValues, 0, newValues.length);
newValues[index] = value;
values = newValues;
if ((sharedFlags & SHARED_VALUES) != 0) {
values = Arrays.copyOf(values, values.length);
sharedFlags &= ~SHARED_VALUES;
}
values[index] = value;
}
/**
......@@ -327,20 +352,34 @@ public class Page {
map.getStore().removePage(pos);
}
public void insert(int index, Object key, Object value, long child,
long count) {
Object[] newKeys = new Object[keys.length + 1];
DataUtils.copyWithGap(keys, newKeys, keys.length, index);
newKeys[index] = key;
public void insertLeaf(int index, Object key, Object value) {
if (((sharedFlags & SHARED_KEYS) == 0) && keys.length > keyCount + 1) {
if (index < keyCount) {
System.arraycopy(keys, index, keys, index + 1, keyCount - index);
System.arraycopy(values, index, values, index + 1, keyCount - index);
}
} else {
int len = keyCount + 6;
Object[] newKeys = new Object[len];
DataUtils.copyWithGap(keys, newKeys, keyCount, index);
keys = newKeys;
if (values != null) {
Object[] newValues = new Object[values.length + 1];
DataUtils.copyWithGap(values, newValues, values.length, index);
newValues[index] = value;
Object[] newValues = new Object[len];
DataUtils.copyWithGap(values, newValues, keyCount, index);
values = newValues;
}
keys[index] = key;
values[index] = value;
keyCount++;
sharedFlags &= ~(SHARED_KEYS | SHARED_VALUES);
totalCount++;
}
if (children != null) {
public void insertNode(int index, Object key, long child, long count) {
Object[] newKeys = new Object[keyCount + 1];
DataUtils.copyWithGap(keys, newKeys, keyCount, index);
newKeys[index] = key;
keys = newKeys;
keyCount++;
long[] newChildren = new long[children.length + 1];
DataUtils.copyWithGap(children, newChildren, children.length, index);
newChildren[index] = child;
......@@ -349,21 +388,24 @@ public class Page {
DataUtils.copyWithGap(counts, newCounts, counts.length, index);
newCounts[index] = count;
counts = newCounts;
sharedFlags &= ~(SHARED_KEYS | SHARED_CHILDREN | SHARED_COUNTS);
totalCount += count;
}
}
public void remove(int index) {
Object[] newKeys = new Object[keys.length - 1];
int keyIndex = index >= keys.length ? index - 1 : index;
DataUtils.copyExcept(keys, newKeys, keys.length, keyIndex);
Object[] newKeys = new Object[keyCount - 1];
int keyIndex = index >= keyCount ? index - 1 : index;
DataUtils.copyExcept(keys, newKeys, keyCount, keyIndex);
keys = newKeys;
sharedFlags &= ~SHARED_KEYS;
if (values != null) {
Object[] newValues = new Object[values.length - 1];
DataUtils.copyExcept(values, newValues, values.length, index);
Object[] newValues = new Object[keyCount - 1];
DataUtils.copyExcept(values, newValues, keyCount, index);
values = newValues;
sharedFlags &= ~SHARED_VALUES;
totalCount--;
}
keyCount--;
if (children != null) {
long countOffset = counts[index];
long[] newChildren = new long[children.length - 1];
......@@ -373,6 +415,7 @@ public class Page {
DataUtils.copyExcept(counts, newCounts,
counts.length, index);
counts = newCounts;
sharedFlags &= ~(SHARED_CHILDREN | SHARED_COUNTS);
totalCount -= countOffset;
}
}
......@@ -399,6 +442,7 @@ public class Page {
}
int len = DataUtils.readVarInt(buff);
keys = new Object[len];
keyCount = len;
int type = buff.get();
boolean node = (type & 1) == DataUtils.PAGE_TYPE_NODE;
boolean compressed = (type & DataUtils.PAGE_COMPRESSED) != 0;
......@@ -448,7 +492,7 @@ public class Page {
buff.putInt(0);
buff.putShort((byte) 0);
DataUtils.writeVarInt(buff, map.getId());
int len = keys.length;
int len = keyCount;
DataUtils.writeVarInt(buff, len);
Compressor compressor = map.getStore().getCompressor();
int type = children != null ? DataUtils.PAGE_TYPE_NODE
......@@ -502,7 +546,7 @@ public class Page {
// length, check, map id, key length, type
int maxLength = 4 + 2 + DataUtils.MAX_VAR_INT_LEN
+ DataUtils.MAX_VAR_INT_LEN + 1;
int len = keys.length;
int len = keyCount;
for (int i = 0; i < len; i++) {
maxLength += map.getKeyType().getMaxLength(keys[i]);
}
......
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