public Ddb(Options options, File databaseDir) throws IOException {
super(options, databaseDir);
seqs.put(GLOBAL_BUCKET, versions.getLastSequence());
this.logCache =
new ChannelCache<String, LogReader0>()
.removalListener(
new RemovalListener<String, LogReader0>() {
public void onRemoval(String fileNumber, LogReader0 logReader) {
if (logReader != null) {
logReader.close();
}
// log
}
})
.loader(
new CacheLoader<String, LogReader0>() {
public LogReader0 load(String key) {
File file =
new File(
Ddb.this.databaseDir,
Filename.logFileName(Long.parseLong(key.split("#")[2])));
FileChannel channel = null;
try {
channel = new FileInputStream(file).getChannel();
LogMonitor logMonitor =
new LogMonitor() {
@Override
public void corruption(long bytes, Throwable reason) {
if (logger.isDebugEnabled()) {
logger.debug(
String.format("corruption of %s bytes", bytes), reason);
}
}
@Override
public void corruption(long bytes, String reason) {
if (logger.isDebugEnabled()) {
logger.debug("corruption of {} bytes: {}", bytes, reason);
}
}
};
return new LogReader0(channel, logMonitor, true, 0);
} catch (FileNotFoundException e) {
throw new IfileNotFoundException("Log file does not exist.", e);
} catch (Exception e) {
if (channel != null) {
try {
channel.close();
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
return null;
}
}
});
}
public long getMaxSeq(int bucket) {
Long seq = seqs.get(bucket);
if (seq != null) {
return seq;
} else {
return -1;
}
}
@Override
public Snapshot writeInternal(WriteBatchImpl updates, WriteOptions options) throws DBException {
checkBackgroundException();
mutex.lock();
try {
long sequenceEnd;
if (updates.size() != 0) {
makeRoomForWrite(false);
// Get sequence numbers for this change set
final long sequenceBegin = versions.getLastSequence() + 1;
sequenceEnd = sequenceBegin + updates.size() - 1;
// Reserve this sequence in the version set
versions.setLastSequence(sequenceEnd);
// Log write
Slice record = writeWriteBatch(updates, sequenceBegin);
try {
log.addRecord(record, options.sync());
} catch (IOException e) {
throw Throwables.propagate(e);
}
// Update memtable
updates.forEach(new InsertIntoHandler(memTable, sequenceBegin));
} else {
sequenceEnd = versions.getLastSequence();
}
seqs.put(options.bucket(), sequenceEnd);
seqs.put(GLOBAL_BUCKET, sequenceEnd); // 全局seq
if (options.snapshot()) {
return new SnapshotImpl(versions.getCurrent(), sequenceEnd);
} else {
return null;
}
} finally {
mutex.unlock();
}
}
@Override
protected void fireSweep(int bucket) {
seqs.remove(bucket);
}
