// Open opens and initializes the Log. Open can recover from previous unclosed shutdowns.
public void Open()
{
if (EnableTraceLogging)
{
Logger.Info(string.Format("tsm1 WAL starting with {0} segment size", SegmentSize));
Logger.Info(string.Format("tsm1 WAL writing to {0}", Path));
}
lock (lockthis)
{
if (!Directory.Exists(Path))
{
Directory.CreateDirectory(Path);
}
List <string> segments = SegmentFileNames(Path);
if (segments != null && segments.Count > 0)
{
string lastSegment = segments[segments.Count - 1];
int id = idFromFileName(lastSegment, out string err);
if (err != null)
{
return;
}
currentSegmentID = id;
FileInfo stat = new FileInfo(lastSegment);
if (stat.Length == 0)
{
try
{
File.Delete(lastSegment);
segments.RemoveAt(segments.Count - 1);
}
catch (Exception ex)
{
Logger.Error("Wal Open Error: " + ex.Message);
}//删除正在使用的wal会抛出异常
}
else
{
FileStream fd = stat.Open(FileMode.Open, FileAccess.ReadWrite, FileShare.Read);
currentSegmentWriter = new WalSegmentWriter(fd);
Interlocked.Add(ref stats.CurrentBytes, stat.Length);
}
long totalOldDiskSize = 0;
foreach (string seg in segments)
{
stat = new FileInfo(seg);
totalOldDiskSize += stat.Length;
if (stat.LastWriteTime.Ticks > LastWriteTime)
{
LastWriteTime = stat.LastWriteTime.Ticks;
}
}
Interlocked.Add(ref stats.OldBytes, totalOldDiskSize);
}
}
}
// CloseSegment closes the current segment if it is non-empty.
public void CloseSegment()
{
lock (lockthis)
{
if (currentSegmentWriter != null)
{
currentSegmentWriter.Flush();
currentSegmentWriter.Close();
Interlocked.Add(ref stats.OldBytes, currentSegmentWriter.Size);
currentSegmentWriter = null;
}
}
}
public void Close()
{
lock (lockthis)
{
if (EnableTraceLogging)
{
Logger.Info(string.Format("Closing {0}", Path));
}
if (currentSegmentWriter != null)
{
currentSegmentWriter.Flush();
currentSegmentWriter.Close();
currentSegmentWriter = null;
}
}
}
// newSegmentFile will close the current segment file and open a new one, updating bookkeeping info on the log.
private void newSegmentFile()
{
currentSegmentID++;
if (currentSegmentWriter != null)
{
currentSegmentWriter.Flush();
currentSegmentWriter.Close();
Interlocked.Add(ref stats.OldBytes, currentSegmentWriter.Size);
}
string fileName = string.Format("{0}{1}{2:D5}.{3}", Path, Constants.WALFilePrefix, currentSegmentID, Constants.WALFileExtension);
FileStream fd = File.Create(fileName);
currentSegmentWriter = new WalSegmentWriter(fd);
LastWriteTime = DateTime.Now.Ticks;
// Reset the current segment size stat
Interlocked.Add(ref stats.CurrentBytes, 0);
}