@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();
}
}