private void __Test_WriteNewCheckpointAddress__(DurableFileStream.FailedCommitCode failedCommitCode)
{
NextTransactionID();
// clear first block on disk before writing log
_fsLog.Seek(0, SeekOrigin.Begin); // go to first block
ClearBuffer();
_bufferIdx = BLOCK_SIZE;
FlushBuffer();
// write log to the first block after clearing
_fsLog.Seek(0, SeekOrigin.Begin); // go to first block
WriteLogRecord ckpWriteRecord = new WriteLogRecord();
ckpWriteRecord.filename = _logPath;
ckpWriteRecord.blockNo = 1;
ckpWriteRecord.count = 8;
ckpWriteRecord.AFIM = BitConverter.GetBytes(_fsLog.Length);
_LSN = 0;
long prev_lsn = LogBegin();
FlushBuffer();
if (failedCommitCode == DurableFileStream.FailedCommitCode.CHECKPOINT_AFTER_LOG_BEGIN)
throw new Exception("Failed Commit: Checkpoint After Log Begin");
prev_lsn = LogWrite(prev_lsn, ckpWriteRecord);
FlushBuffer();
long lastLogPos = _fsLog.Position;
if (failedCommitCode == DurableFileStream.FailedCommitCode.CHECKPOINT_AFTER_LOG_WRITE)
throw new Exception("Failed Commit: Checkpoint After Log Write");
_fsLog.Seek(BLOCK_SIZE, SeekOrigin.Begin);
_fsLog.Write(ckpWriteRecord.AFIM, 0, 8);
_fsLog.Flush(true);
if (failedCommitCode == DurableFileStream.FailedCommitCode.CHECKPOINT_AFTER_DISK_WRITE)
throw new Exception("Failed Commit: Checkpoint After Disk Write");
_fsLog.Seek(lastLogPos, SeekOrigin.Begin); // go to first block
prev_lsn = LogEnd(prev_lsn);
FlushBuffer();
if (failedCommitCode == DurableFileStream.FailedCommitCode.CHECKPOINT_AFTER_LOG_END)
throw new Exception("Failed Commit: Checkpoint After Log End");
_checkpointAddress = _fsLog.Length;
// reset LSN
_fsLog.Seek(0, SeekOrigin.End);
_LSN = _fsLog.Position;
}
private void WriteNewCheckpointAddress()
{
NextTransactionID();
// clear first block on disk before writing log
_fsLog.Seek(0, SeekOrigin.Begin); // go to first block
ClearBuffer();
_bufferIdx = 0;
//_bufferIdx = BLOCK_SIZE;
//FlushBuffer();
// write log to the first block after clearing
_fsLog.Seek(0, SeekOrigin.Begin); // go to first block
WriteLogRecord ckpWriteRecord = new WriteLogRecord();
ckpWriteRecord.filename = _logPath;
ckpWriteRecord.blockNo = 1;
ckpWriteRecord.count = 8;
ckpWriteRecord.AFIM = BitConverter.GetBytes(_fsLog.Length);
_LSN = 0;
long prev_lsn = LogBegin();
prev_lsn = LogWrite(prev_lsn, ckpWriteRecord);
FlushBuffer();
long lastLogPos = _fsLog.Position;
// write checkpoint address to log disk
_fsLog.Seek(CHECKPOINT_POSITION, SeekOrigin.Begin);
_fsLog.Write(ckpWriteRecord.AFIM, 0, 8);
_fsLog.Flush(true);
_fsLog.Seek(lastLogPos, SeekOrigin.Begin); // return to last position
prev_lsn = LogEnd(prev_lsn);
FlushBuffer();
_checkpointAddress = _fsLog.Length;
// reset LSN
_fsLog.Seek(0, SeekOrigin.End);
_LSN = _fsLog.Position;
}
private long LogWrite(long prevLSN, WriteLogRecord record)
{
long lsn = _LSN;
byte[] fileNameInBytes = System.Text.Encoding.UTF8.GetBytes(record.filename);
int filenameLen = fileNameInBytes.Length;
byte[] recordBytes = new byte[48 + filenameLen + record.count];
byte[] inBytes = BitConverter.GetBytes(lsn); // LSN: 8 bytes
Array.Copy(inBytes, 0, recordBytes, 0, 8);
inBytes = BitConverter.GetBytes(recordBytes.Length); // record Length: 4 bytes
Array.Copy(inBytes, 0, recordBytes, 8, 4);
inBytes = BitConverter.GetBytes(prevLSN); // prevLSN: 8 bytes (equal to lsn)
Array.Copy(inBytes, 0, recordBytes, 12, 8);
inBytes = BitConverter.GetBytes(_transactionID); // TransactionID: 4 bytes
Array.Copy(inBytes, 0, recordBytes, 20, 4);
inBytes = BitConverter.GetBytes(WRITE_OPERATION); // Operation: 4 bytes
Array.Copy(inBytes, 0, recordBytes, 24, 4);
inBytes = BitConverter.GetBytes(filenameLen); // filename length in bytes: 4 bytes
Array.Copy(inBytes, 0, recordBytes, 28, 4);
Array.Copy(fileNameInBytes, 0, recordBytes, 32, filenameLen); // filename: inBytes.Length bytes
int idx = 32 + filenameLen;
inBytes = BitConverter.GetBytes(record.blockNo); // blockNo: 8 bytes
Array.Copy(inBytes, 0, recordBytes, idx, 8);
idx += 8;
inBytes = BitConverter.GetBytes(record.count); // count: 4 bytes
Array.Copy(inBytes, 0, recordBytes, idx, 4);
idx += 4;
Array.Copy(record.AFIM, 0, recordBytes, idx, record.count); // AFIM: <record.count> bytes
idx += record.count;
inBytes = BitConverter.GetBytes(CRC32.Compute(recordBytes, 0, idx)); // CRC32: 4 bytes
Array.Copy(inBytes, 0, recordBytes, idx, 4);
idx += 4;
WriteToBuffer(recordBytes, idx);
return lsn;
}
private LogRecord ParseLogRecord(string expectedFilename)
{
long rowPosition = _fsLog.Position;
if (_fsLog.Read(_recoveryBuffer, 0, 32) != 32) // read first 32 bytes
return null;
long lsn = BitConverter.ToInt64(_recoveryBuffer, 0);
if (lsn != rowPosition)
return null;
int recordLength = BitConverter.ToInt32(_recoveryBuffer, 8);
if (recordLength < 32 || recordLength > 8496)
return null;
long prev_lsn = BitConverter.ToInt64(_recoveryBuffer, 12);
if (prev_lsn > lsn)
return null;
int transactionID = BitConverter.ToInt32(_recoveryBuffer, 20);
int operation = BitConverter.ToInt32(_recoveryBuffer, 24);
if (operation < 1 || operation > 4)
return null;
if (operation == WRITE_OPERATION)
{
int filenameLength = BitConverter.ToInt32(_recoveryBuffer, 28);
if ((filenameLength > 255) || (32 + filenameLength > recordLength))
return null;
if (_fsLog.Read(_recoveryBuffer, 32, recordLength - 32) != recordLength - 32)
return null;
string filename = System.Text.Encoding.UTF8.GetString(_recoveryBuffer, 32, filenameLength);
int idx = 32 + filenameLength;
if (filename != expectedFilename)
return null;
if (idx + 12 > recordLength)
return null;
long blockNo = BitConverter.ToInt64(_recoveryBuffer, idx);
int count = BitConverter.ToInt32(_recoveryBuffer, idx + 8);
idx += 12;
if (idx + count + 4 > recordLength)
return null;
byte[] AFIM = new byte[count];
Array.Copy(_recoveryBuffer, idx, AFIM, 0, count);
idx += count;
UInt32 read_crc32 = BitConverter.ToUInt32(_recoveryBuffer, idx);
UInt32 computed_crc32 = CRC32.Compute(_recoveryBuffer, 0, idx);
if (read_crc32 != computed_crc32)
{
return null;
}
WriteLogRecord writeLogRecord = new WriteLogRecord();
writeLogRecord.lsn = lsn;
writeLogRecord.prev_lsn = prev_lsn;
writeLogRecord.transactionID = transactionID;
writeLogRecord.operation = operation;
writeLogRecord.filename = filename;
writeLogRecord.blockNo = blockNo;
writeLogRecord.count = count;
writeLogRecord.AFIM = AFIM;
return writeLogRecord;
}
else
{
UInt32 read_crc32 = BitConverter.ToUInt32(_recoveryBuffer, 28);
UInt32 computed_crc32 = CRC32.Compute(_recoveryBuffer, 0, 28);
if (read_crc32 != computed_crc32)
{
return null;
}
LogRecord logRecord = new LogRecord();
logRecord.lsn = lsn;
logRecord.prev_lsn = prev_lsn;
logRecord.transactionID = transactionID;
logRecord.operation = operation;
return logRecord;
}
}
public void LogWrite(string path, long blockNo, int count, byte[] AFIM)
{
WriteLogRecord writeLogRecord;
if (_writeLogRecordDict.TryGetValue(blockNo, out writeLogRecord))
{
writeLogRecord.AFIM = AFIM;
if (count > writeLogRecord.count)
writeLogRecord.count = count;
}
else
{
writeLogRecord = new WriteLogRecord();
writeLogRecord.filename = path;
writeLogRecord.blockNo = blockNo;
writeLogRecord.count = count;
writeLogRecord.AFIM = AFIM;
_writeLogRecordDict.Add(blockNo, writeLogRecord);
}
}
