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h2database
提交 cc743041 authored 作者: Thomas Mueller's avatar Thomas Mueller
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A persistent tree map (work in progress).

上级 6b4ced6d
隐藏空白字符变更
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正在显示 包含 190 行增加 和 128 行删除
h2/src/tools/org/h2/dev/store/btree/Chunk.java
浏览文件 @ cc743041
......@@ -11,7 +11,17 @@ import java.io.IOException;
import java.util.Properties;
/**
* A chunk of data, containing one or multiple pages
* A chunk of data, containing one or multiple pages.
* <p>
* Chunks are page aligned (each page is usually 4096 bytes).
* There are at most 67 million (2^26) chunks,
* each chunk is at most 2 GB large.
* File format:
* 1 byte: 'c'
* 4 bytes: length
* 4 bytes: chunk id (an incrementing number)
* 8 bytes: metaRootPos
* [ Page ] *
*/
class Chunk {
......@@ -50,6 +60,11 @@ class Chunk {
*/
long metaRootPos;
/**
* The version stored in this chunk.
*/
long version;
Chunk(int id) {
this.id = id;
}
......@@ -61,16 +76,17 @@ class Chunk {
* @return the block
*/
static Chunk fromString(String s) {
Chunk c = new Chunk(0);
Properties prop = new Properties();
try {
prop.load(new ByteArrayInputStream(s.getBytes("UTF-8")));
c.id = Integer.parseInt(prop.get("id").toString());
int id = Integer.parseInt(prop.get("id").toString());
Chunk c = new Chunk(id);
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.metaRootPos = Long.parseLong(prop.get("metaRoot").toString());
c.version = Long.parseLong(prop.get("version").toString());
return c;
} catch (IOException e) {
throw new RuntimeException(e);
......@@ -96,7 +112,8 @@ class Chunk {
"length:" + length + "\n" +
"entryCount:" + entryCount + "\n" +
"liveCount:" + liveCount + "\n" +
"metaRoot:" + metaRootPos + "\n";
"metaRoot:" + metaRootPos + "\n" +
"version:" + version + "\n";
}
}
......
h2/src/tools/org/h2/dev/store/btree/DataUtils.java
浏览文件 @ cc743041
......@@ -45,7 +45,7 @@ public class DataUtils {
* @param x the value
* @return the length in bytes
*/
static int getVarLongLen(long x) {
public static int getVarLongLen(long x) {
int i = 1;
while (true) {
x >>>= 7;
......@@ -97,7 +97,7 @@ public class DataUtils {
* @param buff the source buffer
* @return the value
*/
static long readVarLong(ByteBuffer buff) {
public static long readVarLong(ByteBuffer buff) {
long x = buff.get();
if (x >= 0) {
return x;
......@@ -132,7 +132,7 @@ public class DataUtils {
* @param buff the target buffer
* @param x the value
*/
static void writeVarLong(ByteBuffer buff, long x) {
public static void writeVarLong(ByteBuffer buff, long x) {
while ((x & ~0x7f) != 0) {
buff.put((byte) (0x80 | (x & 0x7f)));
x >>>= 7;
......@@ -148,7 +148,7 @@ public class DataUtils {
* @param oldSize the size of the old array
* @param gapIndex the index of the gap
*/
static void copyWithGap(Object src, Object dst, int oldSize, int gapIndex) {
public static void copyWithGap(Object src, Object dst, int oldSize, int gapIndex) {
if (gapIndex > 0) {
System.arraycopy(src, 0, dst, 0, gapIndex);
}
......@@ -165,7 +165,7 @@ public class DataUtils {
* @param oldSize the size of the old array
* @param removeIndex the index of the entry to remove
*/
static void copyExcept(Object src, Object dst, int oldSize, int removeIndex) {
public static void copyExcept(Object src, Object dst, int oldSize, int removeIndex) {
if (removeIndex > 0 && oldSize > 0) {
System.arraycopy(src, 0, dst, 0, removeIndex);
}
......@@ -184,4 +184,85 @@ public class DataUtils {
buff.rewind();
}
/**
* Convert the length to a length code 0..31. 31 means more than 1 MB.
*
* @param len the length
* @return the length code
*/
public static int encodeLength(int len) {
if (len <= 32) {
return 0;
}
int x = len;
int shift = 0;
while (x > 3) {
shift++;
x = (x >> 1) + (x & 1);
}
shift = Math.max(0, shift - 4);
int code = (shift << 1) + (x & 1);
return Math.min(31, code);
}
/**
* Get the chunk id from the position.
*
* @param pos the position
* @return the chunk id
*/
public static int getChunkId(long pos) {
return (int) (pos >>> 37);
}
/**
* Get the maximum length for the given code.
* For the code 31, Integer.MAX_VALUE is returned.
*
* @param pos the position
* @return the maximum length
*/
public static int getMaxLength(long pos) {
int code = (int) (pos & 31);
if (code == 31) {
return Integer.MAX_VALUE;
}
return (2 + (code & 1)) << ((code >> 1) + 4);
}
/**
* Get the offset from the position.
*
* @param pos the position
* @return the offset
*/
public static int getOffset(long pos) {
return (int) (pos >> 5);
}
/**
* Get the position of this page. The following information is encoded in
* the position: the chunk id, the offset, and the maximum length.
*
* @param chunkId the chunk id
* @param offset the offset
* @param length the length
* @return the position
*/
public static long getPos(int chunkId, int offset, int length) {
return ((long) chunkId << 37) | ((long) offset << 5) | encodeLength(length);
}
/**
* Calculate a check value for the given integer. A check value is mean to
* verify the data is consistent with a high probability, but not meant to
* protect against media failure or deliberate changes.
*
* @param x the value
* @return the check value
*/
public static short getCheckValue(int x) {
return (short) ((x >> 16) ^ x);
}
}
h2/src/tools/org/h2/dev/store/btree/Page.java
浏览文件 @ cc743041
......@@ -17,37 +17,48 @@ import org.h2.compress.Compressor;
* <p>
* For nodes, the key at a given index is larger than the largest key of the
* child at the same index.
* <p>
* File format:
* page length (including length): int
* check value: short
* number of keys: varInt
* type: byte (0: leaf, 1: node; +2: compressed)
* compressed: bytes saved (varInt)
* keys
* leaf: values (one for each key)
* node: children (1 more than keys)
*/
public class Page {
private final BtreeMap<?, ?> map;
private final long version;
private long pos;
private long transaction;
private Object[] keys;
private Object[] values;
private long[] children;
private int cachedCompare;
private Page(BtreeMap<?, ?> map) {
private Page(BtreeMap<?, ?> map, long version) {
this.map = map;
this.version = version;
}
/**
* Create a new page. The arrays are not cloned.
*
* @param map the map
* @param version the version
* @param keys the keys
* @param values the values
* @param children the children
* @return the page
*/
static Page create(BtreeMap<?, ?> map, Object[] keys, Object[] values, long[] children) {
Page p = new Page(map);
static Page create(BtreeMap<?, ?> map, long version, Object[] keys, Object[] values, long[] children) {
Page p = new Page(map, version);
p.keys = keys;
p.values = values;
p.children = children;
p.transaction = map.getTransaction();
p.pos = map.registerTempPage(p);
p.pos = map.getStore().registerTempPage(p);
return p;
}
......@@ -60,7 +71,7 @@ public class Page {
* @return the page
*/
static Page read(FileChannel file, BtreeMap<?, ?> map, long filePos, long pos) {
int maxLength = Page.getMaxLength(pos), length = maxLength;
int maxLength = DataUtils.getMaxLength(pos), length = maxLength;
ByteBuffer buff;
try {
file.position(filePos);
......@@ -75,20 +86,20 @@ public class Page {
} catch (IOException e) {
throw new RuntimeException(e);
}
Page p = new Page(map);
Page p = new Page(map, 0);
p.pos = pos;
p.read(buff, maxLength);
int chunkId = DataUtils.getChunkId(pos);
int offset = DataUtils.getOffset(pos);
p.read(buff, chunkId, offset, maxLength);
return p;
}
private Page copyOnWrite() {
long t = map.getTransaction();
if (transaction == t) {
private Page copyOnWrite(long writeVersion) {
if (version == writeVersion) {
return this;
}
map.removePage(pos);
Page newPage = create(map, keys, values, children);
newPage.transaction = t;
getStore().removePage(pos);
Page newPage = create(map, writeVersion, keys, values, children);
newPage.cachedCompare = cachedCompare;
return newPage;
}
......@@ -297,7 +308,7 @@ public class Page {
System.arraycopy(values, 0, aValues, 0, a);
System.arraycopy(values, a, bValues, 0, b);
values = aValues;
Page newPage = create(map, bKeys, bValues, null);
Page newPage = create(map, version, bKeys, bValues, null);
return newPage;
}
......@@ -313,7 +324,7 @@ public class Page {
System.arraycopy(children, 0, aChildren, 0, a + 1);
System.arraycopy(children, a + 1, bChildren, 0, b);
children = aChildren;
Page newPage = create(map, bKeys, null, bChildren);
Page newPage = create(map, version, bKeys, null, bChildren);
return newPage;
}
......@@ -322,18 +333,19 @@ public class Page {
*
* @param map the map
* @param p the page
* @param writeVersion the write version
* @param key the key
* @param value the value
* @return the root page
*/
static Page put(BtreeMap<?, ?> map, Page p, Object key, Object value) {
static Page put(BtreeMap<?, ?> map, Page p, long writeVersion, Object key, Object value) {
if (p == null) {
Object[] keys = { key };
Object[] values = { value };
p = create(map, keys, values, null);
p = create(map, writeVersion, keys, values, null);
return p;
}
p = p.copyOnWrite();
p = p.copyOnWrite(writeVersion);
Page top = p;
Page parent = null;
int parentIndex = 0;
......@@ -350,7 +362,7 @@ public class Page {
if (parent == null) {
Object[] keys = { k };
long[] children = { p.getPos(), split.getPos() };
top = create(map, keys, null, children);
top = create(map, writeVersion, keys, null, children);
p = top;
} else {
parent.insert(parentIndex, k, null, split.getPos());
......@@ -373,7 +385,7 @@ public class Page {
if (parent == null) {
Object[] keys = { k };
long[] children = { p.getPos(), split.getPos() };
top = create(map, keys, null, children);
top = create(map, writeVersion, keys, null, children);
} else {
parent.insert(parentIndex, k, null, split.getPos());
}
......@@ -388,7 +400,7 @@ public class Page {
parent = p;
parentIndex = index;
p = map.readPage(p.children[index]);
p = p.copyOnWrite();
p = p.copyOnWrite(writeVersion);
}
return top;
}
......@@ -418,25 +430,26 @@ public class Page {
map.readPage(c).removeAllRecursive();
}
}
map.removePage(pos);
getStore().removePage(pos);
}
/**
* Remove a key-value pair.
*
* @param p the root page
* @param writeVersion the write version
* @param key the key
* @return the new root page
*/
static Page remove(Page p, Object key) {
static Page remove(Page p, long writeVersion, Object key) {
int index = p.findKey(key);
if (p.isLeaf()) {
if (index >= 0) {
if (p.keyCount() == 1) {
p.map.removePage(p.pos);
p.getStore().removePage(p.pos);
return null;
}
p = p.copyOnWrite();
p = p.copyOnWrite(writeVersion);
p.remove(index);
} else {
// not found
......@@ -450,19 +463,19 @@ public class Page {
index++;
}
Page c = p.map.readPage(p.children[index]);
Page c2 = remove(c, key);
Page c2 = remove(c, writeVersion, key);
if (c2 == c) {
// not found
} else if (c2 == null) {
// child was deleted
p = p.copyOnWrite();
p = p.copyOnWrite(writeVersion);
p.remove(index);
if (p.keyCount() == 0) {
p.map.removePage(p.pos);
p.getStore().removePage(p.pos);
p = p.map.readPage(p.children[0]);
}
} else {
p = p.copyOnWrite();
p = p.copyOnWrite(writeVersion);
p.setChild(index, c2.pos);
}
return p;
......@@ -504,31 +517,36 @@ public class Page {
}
}
private void read(ByteBuffer buff, int maxLength) {
private void read(ByteBuffer buff, int chunkId, int offset, int maxLength) {
int start = buff.position();
int len = buff.getInt();
if (len > maxLength) {
throw new RuntimeException("Length too large, expected < " + maxLength + " got " + len);
}
int mapId = DataUtils.readVarInt(buff);
if (mapId != map.getId()) {
throw new RuntimeException("Page pos mismatch, expected " + map.getId() + " got " + mapId);
int pageLength = buff.getInt();
if (pageLength > maxLength) {
throw new RuntimeException("Length too large, expected =< " + maxLength + " got " + pageLength);
}
short check = buff.getShort();
int len = DataUtils.readVarInt(buff);
int checkTest = DataUtils.getCheckValue(chunkId) ^
DataUtils.getCheckValue(map.getId()) ^
DataUtils.getCheckValue(offset) ^
DataUtils.getCheckValue(pageLength) ^
DataUtils.getCheckValue(len);
if (check != (short) checkTest) {
throw new RuntimeException("Error in check value, expected " + checkTest + " got " + check);
}
keys = new Object[len];
int type = buff.get();
boolean node = (type & 1) != 0;
boolean compressed = (type & 2) != 0;
if (compressed) {
Compressor compressor = map.getStore().getCompressor();
int lenAdd = DataUtils.readVarInt(buff);
int compLen = len + start - buff.position();
int compLen = pageLength + start - buff.position();
byte[] comp = new byte[compLen];
buff.get(comp);
byte[] exp = new byte[compLen + lenAdd];
compressor.expand(comp, 0, compLen, exp, 0, exp.length);
buff = ByteBuffer.wrap(exp);
}
len = DataUtils.readVarInt(buff);
keys = new Object[len];
for (int i = 0; i < len; i++) {
keys[i] = map.getKeyType().read(buff);
}
......@@ -554,13 +572,13 @@ public class Page {
private void write(ByteBuffer buff, int chunkId) {
int start = buff.position();
buff.putInt(0);
DataUtils.writeVarInt(buff, map.getId());
buff.putShort((byte) 0);
int len = keys.length;
DataUtils.writeVarInt(buff, len);
Compressor compressor = map.getStore().getCompressor();
int type = children != null ? 1 : 0;
buff.put((byte) type);
int compressStart = buff.position();
int len = keys.length;
DataUtils.writeVarInt(buff, len);
for (int i = 0; i < len; i++) {
map.getKeyType().write(buff, keys[i]);
}
......@@ -574,22 +592,29 @@ public class Page {
}
}
if (compressor != null) {
len = buff.position() - compressStart;
byte[] exp = new byte[len];
int expLen = buff.position() - compressStart;
byte[] exp = new byte[expLen];
buff.position(compressStart);
buff.get(exp);
byte[] comp = new byte[exp.length * 2];
int compLen = compressor.compress(exp, exp.length, comp, 0);
if (compLen + DataUtils.getVarIntLen(compLen - len) < len) {
if (compLen + DataUtils.getVarIntLen(compLen - expLen) < expLen) {
buff.position(compressStart - 1);
buff.put((byte) (type + 2));
DataUtils.writeVarInt(buff, len - compLen);
DataUtils.writeVarInt(buff, expLen - compLen);
buff.put(comp, 0, compLen);
}
}
len = buff.position() - start;
buff.putInt(start, len);
this.pos = Page.getPos(chunkId, start, len);
int pageLength = buff.position() - start;
buff.putInt(start, pageLength);
int check =
DataUtils.getCheckValue(chunkId) ^
DataUtils.getCheckValue(map.getId()) ^
DataUtils.getCheckValue(start) ^
DataUtils.getCheckValue(pageLength) ^
DataUtils.getCheckValue(len);
buff.putShort(start + 4, (short) check);
this.pos = DataUtils.getPos(chunkId, start, pageLength);
}
/**
......@@ -598,9 +623,9 @@ public class Page {
* @return the next page id
*/
int getMaxLengthTempRecursive() {
int maxLength = 4 + DataUtils.MAX_VAR_INT_LEN + 1;
// length, check, key length, type
int maxLength = 4 + 2 + DataUtils.MAX_VAR_INT_LEN + 1;
int len = keys.length;
maxLength += DataUtils.MAX_VAR_INT_LEN;
for (int i = 0; i < len; i++) {
maxLength += map.getKeyType().getMaxLength(keys[i]);
}
......@@ -661,73 +686,12 @@ public class Page {
return count;
}
/**
* Get the chunk id from the position.
*
* @param pos the position
* @return the chunk id
*/
static int getChunkId(long pos) {
return (int) (pos >>> 37);
}
/**
* Get the offset from the position.
*
* @param pos the position
* @return the offset
*/
public static long getOffset(long pos) {
return (int) (pos >> 5);
}
/**
* Get the position of this page. The following information is encoded in
* the position: the chunk id, the offset, and the maximum length.
*
* @param chunkId the chunk id
* @param offset the offset
* @param length the length
* @return the position
*/
static long getPos(int chunkId, int offset, int length) {
return ((long) chunkId << 37) | ((long) offset << 5) | encodeLength(length);
}
/**
* Convert the length to a length code 0..31. 31 means more than 1 MB.
*
* @param len the length
* @return the length code
*/
public static int encodeLength(int len) {
if (len <= 32) {
return 0;
}
int x = len;
int shift = 0;
while (x > 3) {
shift++;
x = (x >> 1) + (x & 1);
}
shift = Math.max(0, shift - 4);
int code = (shift << 1) + (x & 1);
return Math.min(31, code);
BtreeMapStore getStore() {
return map.getStore();
}
/**
* Get the maximum length for the given code.
* For the code 31, Integer.MAX_VALUE is returned.
*
* @param pos the position
* @return the maximum length
*/
public static int getMaxLength(long pos) {
int code = (int) (pos & 31);
if (code == 31) {
return Integer.MAX_VALUE;
}
return (2 + (code & 1)) << ((code >> 1) + 4);
long getVersion() {
return version;
}
}
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