private void ProcessLogRecord(SeqReadResult result)
{
switch (result.LogRecord.RecordType)
{
case LogRecordType.Prepare:
{
var record = (PrepareLogRecord)result.LogRecord;
ProcessPrepareRecord(record, result.Eof);
break;
}
case LogRecordType.Commit:
{
_commitsAfterEof = !result.Eof;
var record = (CommitLogRecord)result.LogRecord;
ProcessCommitRecord(record, result.Eof);
break;
}
case LogRecordType.System:
{
var record = (SystemLogRecord)result.LogRecord;
ProcessSystemRecord(record);
break;
}
default:
throw new ArgumentOutOfRangeException();
}
if (result.Eof && result.LogRecord.RecordType != LogRecordType.Commit && _commitsAfterEof)
{
_commitsAfterEof = false;
_masterBus.Publish(new StorageMessage.TfEofAtNonCommitRecord());
}
}
private void ProcessLogRecord(SeqReadResult result)
{
switch (result.LogRecord.RecordType)
{
case LogRecordType.Prepare:
{
var record = (PrepareLogRecord)result.LogRecord;
ProcessPrepareRecord(record);
break;
}
case LogRecordType.Commit:
{
var record = (CommitLogRecord)result.LogRecord;
ProcessCommitRecord(record);
break;
}
case LogRecordType.System:
{
var record = (SystemLogRecord)result.LogRecord;
ProcessSystemRecord(record);
break;
}
default:
throw new ArgumentOutOfRangeException();
}
}
private SeqReadResult TryReadPrevInternal(int retries)
{
while (true)
{
var pos = _curPos;
var writerChk = _writerCheckpoint.Read();
// we allow == writerChk, that means read the very last record
if (pos > writerChk)
{
throw new Exception(string.Format("Requested position {0} is greater than writer checkpoint {1} when requesting to read previous record from TF.", pos, writerChk));
}
if (pos <= 0)
{
return(SeqReadResult.Failure);
}
var chunk = _db.Manager.GetChunkFor(pos);
bool readLast = false;
if (pos == chunk.ChunkHeader.ChunkStartPosition)
{
// we are exactly at the boundary of physical chunks
// so we switch to previous chunk and request TryReadLast
readLast = true;
chunk = _db.Manager.GetChunkFor(pos - 1);
}
RecordReadResult result;
try
{
result = readLast ? chunk.TryReadLast() : chunk.TryReadClosestBackward(chunk.ChunkHeader.GetLocalLogPosition(pos));
CountRead(chunk.IsCached);
}
catch (FileBeingDeletedException)
{
if (retries > MaxRetries)
{
throw new Exception(string.Format("Got a file that was being deleted {0} times from TFChunkDb, likely a bug there.", MaxRetries));
}
return(TryReadPrevInternal(retries + 1));
}
if (result.Success)
{
_curPos = chunk.ChunkHeader.ChunkStartPosition + result.NextPosition;
var postPos = result.LogRecord.GetNextLogPosition(result.LogRecord.LogPosition, result.RecordLength);
var eof = postPos == writerChk;
var res = new SeqReadResult(true, eof, result.LogRecord, result.RecordLength, result.LogRecord.LogPosition, postPos);
return(res);
}
// we are the beginning of chunk, so need to switch to previous one
// to do that we set cur position to the exact boundary position between current and previous chunk,
// this will be handled correctly on next iteration
_curPos = chunk.ChunkHeader.ChunkStartPosition;
}
}
private static bool TryReadNextLogRecord(TFReaderLease reader, out SeqReadResult result)
{
result = reader.TryReadNext();
return(result.Success);
}
