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/*
* Copyright 2004-2022 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.mvstore.db;
import java.io.InputStream;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.h2.api.ErrorCode;
import org.h2.command.ddl.CreateTableData;
import org.h2.engine.Constants;
import org.h2.engine.Database;
import org.h2.engine.SessionLocal;
import org.h2.message.DbException;
import org.h2.mvstore.DataUtils;
import org.h2.mvstore.FileStore;
import org.h2.mvstore.MVStore;
import org.h2.mvstore.MVStoreException;
import org.h2.mvstore.MVStoreTool;
import org.h2.mvstore.tx.Transaction;
import org.h2.mvstore.tx.TransactionStore;
import org.h2.mvstore.type.MetaType;
import org.h2.store.InDoubtTransaction;
import org.h2.store.fs.FileChannelInputStream;
import org.h2.store.fs.FileUtils;
import org.h2.util.StringUtils;
import org.h2.util.Utils;
/**
* A store with open tables.
*/
public final class Store {
/**
* Convert password from byte[] to char[].
*
* @param key password as byte[]
* @return password as char[].
*/
static char[] decodePassword(byte[] key) {
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));
}
return password;
}
/**
* The map of open tables.
* Key: the map name, value: the table.
*/
private final ConcurrentHashMap tableMap = new ConcurrentHashMap<>();
/**
* The store.
*/
private final MVStore mvStore;
/**
* The transaction store.
*/
private final TransactionStore transactionStore;
private long statisticsStart;
private int temporaryMapId;
private final boolean encrypted;
private final String fileName;
/**
* Creates the store.
*
* @param db the database
*/
public Store(Database db) {
byte[] key = db.getFileEncryptionKey();
String dbPath = db.getDatabasePath();
MVStore.Builder builder = new MVStore.Builder();
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);
}
int autoCompactFillRate = db.getSettings().autoCompactFillRate;
if (autoCompactFillRate <= 100) {
builder.autoCompactFillRate(autoCompactFillRate);
}
}
if (key != null) {
encrypted = true;
builder.encryptionKey(decodePassword(key));
}
if (db.getSettings().compressData) {
builder.compress();
// use a larger page split size to improve the compression ratio
builder.pageSplitSize(64 * 1024);
}
builder.backgroundExceptionHandler((t, e) -> db.setBackgroundException(DbException.convert(e)));
// always start without background thread first, and if necessary,
// it will be set up later, after db has been fully started,
// otherwise background thread would compete for store lock
// with maps opening procedure
builder.autoCommitDisabled();
}
this.encrypted = encrypted;
try {
this.mvStore = builder.open();
FileStore fs = mvStore.getFileStore();
fileName = fs != null ? fs.getFileName() : null;
if (!db.getSettings().reuseSpace) {
mvStore.setReuseSpace(false);
}
mvStore.setVersionsToKeep(0);
this.transactionStore = new TransactionStore(mvStore,
new MetaType<>(db, mvStore.backgroundExceptionHandler), new ValueDataType(db, null),
db.getLockTimeout());
} catch (MVStoreException e) {
throw convertMVStoreException(e);
}
}
/**
* Convert a MVStoreException to the similar exception used
* for the table/sql layers.
*
* @param e the illegal state exception
* @return the database exception
*/
DbException convertMVStoreException(MVStoreException e) {
switch (e.getErrorCode()) {
case DataUtils.ERROR_CLOSED:
throw DbException.get(ErrorCode.DATABASE_IS_CLOSED, e, fileName);
case DataUtils.ERROR_FILE_CORRUPT:
if (encrypted) {
throw DbException.get(ErrorCode.FILE_ENCRYPTION_ERROR_1, e, fileName);
}
throw DbException.get(ErrorCode.FILE_CORRUPTED_1, e, fileName);
case DataUtils.ERROR_FILE_LOCKED:
throw DbException.get(ErrorCode.DATABASE_ALREADY_OPEN_1, e, fileName);
case DataUtils.ERROR_READING_FAILED:
case DataUtils.ERROR_WRITING_FAILED:
throw DbException.get(ErrorCode.IO_EXCEPTION_1, e, fileName);
default:
throw DbException.get(ErrorCode.GENERAL_ERROR_1, e, e.getMessage());
}
}
public MVStore getMvStore() {
return mvStore;
}
public TransactionStore getTransactionStore() {
return transactionStore;
}
/**
* Get MVTable by table name.
*
* @param tableName table name
* @return MVTable
*/
public MVTable getTable(String tableName) {
return tableMap.get(tableName);
}
/**
* Create a table.
*
* @param data CreateTableData
* @return table created
*/
public MVTable createTable(CreateTableData data) {
try {
MVTable table = new MVTable(data, this);
tableMap.put(table.getMapName(), table);
return table;
} catch (MVStoreException e) {
throw convertMVStoreException(e);
}
}
/**
* Remove a table.
*
* @param table the table
*/
public void removeTable(MVTable table) {
try {
tableMap.remove(table.getMapName());
} catch (MVStoreException e) {
throw convertMVStoreException(e);
}
}
/**
* Store all pending changes.
*/
public void flush() {
FileStore s = mvStore.getFileStore();
if (s == null || s.isReadOnly()) {
return;
}
if (!mvStore.compact(50, 4 * 1024 * 1024)) {
mvStore.commit();
}
}
/**
* Close the store, without persisting changes.
*/
public void closeImmediately() {
if (!mvStore.isClosed()) {
mvStore.closeImmediately();
}
}
/**
* Remove all temporary maps.
*
* @param objectIds the ids of the objects to keep
*/
public void removeTemporaryMaps(BitSet objectIds) {
for (String mapName : mvStore.getMapNames()) {
if (mapName.startsWith("temp.")) {
mvStore.removeMap(mapName);
} else if (mapName.startsWith("table.") || mapName.startsWith("index.")) {
int id = StringUtils.parseUInt31(mapName, mapName.indexOf('.') + 1, mapName.length());
if (!objectIds.get(id)) {
mvStore.removeMap(mapName);
}
}
}
}
/**
* 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(SessionLocal session, String transactionName) {
Transaction t = session.getTransaction();
t.setName(transactionName);
t.prepare();
mvStore.commit();
}
public ArrayList getInDoubtTransactions() {
List list = transactionStore.getOpenTransactions();
ArrayList result = Utils.newSmallArrayList();
for (Transaction t : list) {
if (t.getStatus() == Transaction.STATUS_PREPARED) {
result.add(new MVInDoubtTransaction(mvStore, 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) {
mvStore.setCacheSize(Math.max(1, kb / 1024));
}
public InputStream getInputStream() {
FileChannel fc = mvStore.getFileStore().getEncryptedFile();
if (fc == null) {
fc = mvStore.getFileStore().getFile();
}
return new FileChannelInputStream(fc, false);
}
/**
* Force the changes to disk.
*/
public void sync() {
flush();
mvStore.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
*/
@SuppressWarnings("unused")
public void compactFile(int maxCompactTime) {
mvStore.compactFile(maxCompactTime);
}
/**
* Close the store. Pending changes are persisted.
* If time is allocated for housekeeping, chunks with a low
* fill rate are compacted, and some chunks are put next to each other.
* If time is unlimited then full compaction is performed, which uses
* different algorithm - opens alternative temp store and writes all live
* data there, then replaces this store with a new one.
*
* @param allowedCompactionTime time (in milliseconds) alloted for file
* compaction activity, 0 means no compaction,
* -1 means unlimited time (full compaction)
*/
public void close(int allowedCompactionTime) {
try {
FileStore fileStore = mvStore.getFileStore();
if (!mvStore.isClosed() && fileStore != null) {
boolean compactFully = allowedCompactionTime == -1;
if (fileStore.isReadOnly()) {
compactFully = false;
} else {
transactionStore.close();
}
if (compactFully) {
allowedCompactionTime = 0;
}
mvStore.close(allowedCompactionTime);
String fileName = fileStore.getFileName();
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 (MVStoreException e) {
int errorCode = e.getErrorCode();
if (errorCode == DataUtils.ERROR_WRITING_FAILED) {
// disk full - ok
} else if (errorCode == DataUtils.ERROR_FILE_CORRUPT) {
// wrong encryption key - ok
}
mvStore.closeImmediately();
throw DbException.get(ErrorCode.IO_EXCEPTION_1, e, "Closing");
}
}
/**
* Start collecting statistics.
*/
public void statisticsStart() {
FileStore fs = mvStore.getFileStore();
statisticsStart = fs == null ? 0 : fs.getReadCount();
}
/**
* Stop collecting statistics.
*
* @return the statistics
*/
public Map statisticsEnd() {
HashMap map = new HashMap<>();
FileStore fs = mvStore.getFileStore();
int reads = fs == null ? 0 : (int) (fs.getReadCount() - statisticsStart);
map.put("reads", reads);
return map;
}
}
