/*
* Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.mvstore.db;
import java.io.InputStream;
import java.lang.Thread.UncaughtExceptionHandler;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import org.h2.api.ErrorCode;
import org.h2.api.TableEngine;
import org.h2.command.ddl.CreateTableData;
import org.h2.engine.Constants;
import org.h2.engine.Database;
import org.h2.engine.Session;
import org.h2.message.DbException;
import org.h2.mvstore.DataUtils;
import org.h2.mvstore.FileStore;
import org.h2.mvstore.MVMap;
import org.h2.mvstore.MVStore;
import org.h2.mvstore.MVStoreTool;
import org.h2.mvstore.db.TransactionStore.Transaction;
import org.h2.mvstore.db.TransactionStore.TransactionMap;
import org.h2.store.InDoubtTransaction;
import org.h2.store.fs.FileChannelInputStream;
import org.h2.store.fs.FileUtils;
import org.h2.table.TableBase;
import org.h2.util.BitField;
import org.h2.util.New;
/**
* A table engine that internally uses the MVStore.
*/
public class MVTableEngine implements TableEngine {
/**
* Initialize the MVStore.
*
* @param db the database
* @return the store
*/
public static Store init(final Database db) {
Store store = db.getMvStore();
if (store != null) {
return store;
}
byte[] key = db.getFileEncryptionKey();
String dbPath = db.getDatabasePath();
MVStore.Builder builder = new MVStore.Builder();
store = new Store();
boolean encrypted = false;
if (dbPath != null) {
String fileName = dbPath + Constants.SUFFIX_MV_FILE;
MVStoreTool.compactCleanUp(fileName);
builder.fileName(fileName);
builder.pageSplitSize(db.getPageSize());
if (db.isReadOnly()) {
builder.readOnly();
} else {
// possibly create the directory
boolean exists = FileUtils.exists(fileName);
if (exists && !FileUtils.canWrite(fileName)) {
// read only
} else {
String dir = FileUtils.getParent(fileName);
FileUtils.createDirectories(dir);
}
}
if (key != null) {
encrypted = true;
char[] password = new char[key.length / 2];
for (int i = 0; i < password.length; i++) {
password[i] = (char) (((key[i + i] & 255) << 16) |
((key[i + i + 1]) & 255));
}
builder.encryptionKey(password);
}
if (db.getSettings().compressData) {
builder.compress();
// use a larger page split size to improve the compression ratio
builder.pageSplitSize(64 * 1024);
}
builder.backgroundExceptionHandler(new UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread t, Throwable e) {
db.setBackgroundException(DbException.convert(e));
}
});
}
store.open(db, builder, encrypted);
db.setMvStore(store);
return store;
}
@Override
public TableBase createTable(CreateTableData data) {
Database db = data.session.getDatabase();
Store store = init(db);
MVTable table = new MVTable(data, store);
table.init(data.session);
store.tableMap.put(table.getMapName(), table);
return table;
}
/**
* A store with open tables.
*/
public static class Store {
/**
* The map of open tables.
* Key: the map name, value: the table.
*/
final ConcurrentHashMap<String, MVTable> tableMap =
new ConcurrentHashMap<String, MVTable>();
/**
* The store.
*/
private MVStore store;
/**
* The transaction store.
*/
private TransactionStore transactionStore;
private long statisticsStart;
private int temporaryMapId;
private boolean encrypted;
private String fileName;
/**
* Open the store for this database.
*
* @param db the database
* @param builder the builder
* @param encrypted whether the store is encrypted
*/
void open(Database db, MVStore.Builder builder, boolean encrypted) {
this.encrypted = encrypted;
try {
this.store = builder.open();
FileStore fs = store.getFileStore();
if (fs != null) {
this.fileName = fs.getFileName();
}
if (!db.getSettings().reuseSpace) {
store.setReuseSpace(false);
}
this.transactionStore = new TransactionStore(
store,
new ValueDataType(null, db, null));
transactionStore.init();
} catch (IllegalStateException e) {
throw convertIllegalStateException(e);
}
}
/**
* Convert the illegal state exception to the correct database
* exception.
*
* @param e the illegal state exception
* @return the database exception
*/
DbException convertIllegalStateException(IllegalStateException e) {
int errorCode = DataUtils.getErrorCode(e.getMessage());
if (errorCode == DataUtils.ERROR_FILE_CORRUPT) {
if (encrypted) {
throw DbException.get(
ErrorCode.FILE_ENCRYPTION_ERROR_1,
e, fileName);
}
} else if (errorCode == DataUtils.ERROR_FILE_LOCKED) {
throw DbException.get(
ErrorCode.DATABASE_ALREADY_OPEN_1,
e, fileName);
} else if (errorCode == DataUtils.ERROR_READING_FAILED) {
throw DbException.get(
ErrorCode.IO_EXCEPTION_1,
e, fileName);
}
throw DbException.get(
ErrorCode.FILE_CORRUPTED_1,
e, fileName);
}
public MVStore getStore() {
return store;
}
public TransactionStore getTransactionStore() {
return transactionStore;
}
public HashMap<String, MVTable> getTables() {
return new HashMap<String, MVTable>(tableMap);
}
/**
* Remove a table.
*
* @param table the table
*/
public void removeTable(MVTable table) {
tableMap.remove(table.getMapName());
}
/**
* Store all pending changes.
*/
public void flush() {
FileStore s = store.getFileStore();
if (s == null || s.isReadOnly()) {
return;
}
if (!store.compact(50, 4 * 1024 * 1024)) {
store.commit();
}
}
/**
* Close the store, without persisting changes.
*/
public void closeImmediately() {
if (store.isClosed()) {
return;
}
store.closeImmediately();
}
/**
* Commit all transactions that are in the committing state, and
* rollback all open transactions.
*/
public void initTransactions() {
List<Transaction> list = transactionStore.getOpenTransactions();
for (Transaction t : list) {
if (t.getStatus() == Transaction.STATUS_COMMITTING) {
t.commit();
} else if (t.getStatus() != Transaction.STATUS_PREPARED) {
t.rollback();
}
}
}
/**
* Remove all temporary maps.
*
* @param objectIds the ids of the objects to keep
*/
public void removeTemporaryMaps(BitField objectIds) {
for (String mapName : store.getMapNames()) {
if (mapName.startsWith("temp.")) {
MVMap<?, ?> map = store.openMap(mapName);
store.removeMap(map);
} else if (mapName.startsWith("table.") || mapName.startsWith("index.")) {
int id = Integer.parseInt(mapName.substring(1 + mapName.indexOf(".")));
//上层的SYS表中没有对应id的表和索引元数据了，这时与MVStore中的meta表存放的不一致，所以删除
if (!objectIds.get(id)) {
ValueDataType keyType = new ValueDataType(null, null, null);
ValueDataType valueType = new ValueDataType(null, null, null);
Transaction t = transactionStore.begin();
TransactionMap<?, ?> m = t.openMap(mapName, keyType, valueType);
transactionStore.removeMap(m);
t.commit();
}
}
}
}
/**
* Get the name of the next available temporary map.
*
* @return the map name
*/
public synchronized String nextTemporaryMapName() {
return "temp." + temporaryMapId++;
}
/**
* Prepare a transaction.
*
* @param session the session
* @param transactionName the transaction name (may be null)
*/
public void prepareCommit(Session session, String transactionName) {
Transaction t = session.getTransaction();
t.setName(transactionName);
t.prepare();
store.commit();
}
public ArrayList<InDoubtTransaction> getInDoubtTransactions() {
List<Transaction> list = transactionStore.getOpenTransactions();
ArrayList<InDoubtTransaction> result = New.arrayList();
for (Transaction t : list) {
if (t.getStatus() == Transaction.STATUS_PREPARED) {
result.add(new MVInDoubtTransaction(store, t));
}
}
return result;
}
/**
* Set the maximum memory to be used by the cache.
*
* @param kb the maximum size in KB
*/
public void setCacheSize(int kb) {
store.setCacheSize(Math.max(1, kb / 1024));
}
public InputStream getInputStream() {
FileChannel fc = store.getFileStore().getEncryptedFile();
if (fc == null) {
fc = store.getFileStore().getFile();
}
return new FileChannelInputStream(fc, false);
}
/**
* Force the changes to disk.
*/
public void sync() {
flush();
store.sync();
}
/**
* Compact the database file, that is, compact blocks that have a low
* fill rate, and move chunks next to each other. This will typically
* shrink the database file. Changes are flushed to the file, and old
* chunks are overwritten.
*
* @param maxCompactTime the maximum time in milliseconds to compact
*/
public void compactFile(long maxCompactTime) {
store.setRetentionTime(0);
long start = System.nanoTime();
while (store.compact(95, 16 * 1024 * 1024)) {
store.sync();
store.compactMoveChunks(95, 16 * 1024 * 1024);
long time = System.nanoTime() - start;
if (time > TimeUnit.MILLISECONDS.toNanos(maxCompactTime)) {
break;
}
}
}
/**
* Close the store. Pending changes are persisted. Chunks with a low
* fill rate are compacted, but old chunks are kept for some time, so
* most likely the database file will not shrink.
*
* @param maxCompactTime the maximum time in milliseconds to compact
*/
public void close(long maxCompactTime) {
try {
if (!store.isClosed() && store.getFileStore() != null) {
boolean compactFully = false;
if (!store.getFileStore().isReadOnly()) {
transactionStore.close();
if (maxCompactTime == Long.MAX_VALUE) {
compactFully = true;
}
}
String fileName = store.getFileStore().getFileName();
store.close();
if (compactFully && FileUtils.exists(fileName)) {
// the file could have been deleted concurrently,
// so only compact if the file still exists
MVStoreTool.compact(fileName, true);
}
}
} catch (IllegalStateException e) {
int errorCode = DataUtils.getErrorCode(e.getMessage());
if (errorCode == DataUtils.ERROR_WRITING_FAILED) {
// disk full - ok
} else if (errorCode == DataUtils.ERROR_FILE_CORRUPT) {
// wrong encryption key - ok
}
store.closeImmediately();
throw DbException.get(ErrorCode.IO_EXCEPTION_1, e, "Closing");
}
}
/**
* Start collecting statistics.
*/
public void statisticsStart() {
FileStore fs = store.getFileStore();
statisticsStart = fs == null ? 0 : fs.getReadCount();
}
/**
* Stop collecting statistics.
*
* @return the statistics
*/
public Map<String, Integer> statisticsEnd() {
HashMap<String, Integer> map = New.hashMap();
FileStore fs = store.getFileStore();
int reads = fs == null ? 0 : (int) (fs.getReadCount() - statisticsStart);
map.put("reads", reads);
return map;
}
}
/**
* An in-doubt transaction.
*/
private static class MVInDoubtTransaction implements InDoubtTransaction {
private final MVStore store;
private final Transaction transaction;
private int state = InDoubtTransaction.IN_DOUBT;
MVInDoubtTransaction(MVStore store, Transaction transaction) {
this.store = store;
this.transaction = transaction;
}
@Override
public void setState(int state) {
if (state == InDoubtTransaction.COMMIT) {
transaction.commit();
} else {
transaction.rollback();
}
store.commit();
this.state = state;
}
@Override
public String getState() {
switch (state) {
case IN_DOUBT:
return "IN_DOUBT";
case COMMIT:
return "COMMIT";
case ROLLBACK:
return "ROLLBACK";
default:
throw DbException.throwInternalError("state="+state);
}
}
@Override
public String getTransactionName() {
return transaction.getName();
}
}
}