/// <exception cref="System.IO.IOException"/>
internal static void DoMerge(CheckpointSignature sig, RemoteEditLogManifest manifest
, bool loadImage, FSImage dstImage, FSNamesystem dstNamesystem)
{
NNStorage dstStorage = dstImage.GetStorage();
dstStorage.SetStorageInfo(sig);
if (loadImage)
{
FilePath file = dstStorage.FindImageFile(NNStorage.NameNodeFile.Image, sig.mostRecentCheckpointTxId
);
if (file == null)
{
throw new IOException("Couldn't find image file at txid " + sig.mostRecentCheckpointTxId
+ " even though it should have " + "just been downloaded");
}
dstNamesystem.WriteLock();
try
{
dstImage.ReloadFromImageFile(file, dstNamesystem);
}
finally
{
dstNamesystem.WriteUnlock();
}
dstNamesystem.ImageLoadComplete();
}
// error simulation code for junit test
CheckpointFaultInjector.GetInstance().DuringMerge();
Checkpointer.RollForwardByApplyingLogs(manifest, dstImage, dstNamesystem);
// The following has the side effect of purging old fsimages/edit logs.
dstImage.SaveFSImageInAllDirs(dstNamesystem, dstImage.GetLastAppliedTxId());
dstStorage.WriteAll();
}
/// <exception cref="System.IO.IOException"/>
internal static void RollForwardByApplyingLogs(RemoteEditLogManifest manifest, FSImage
dstImage, FSNamesystem dstNamesystem)
{
NNStorage dstStorage = dstImage.GetStorage();
IList <EditLogInputStream> editsStreams = Lists.NewArrayList();
foreach (RemoteEditLog log in manifest.GetLogs())
{
if (log.GetEndTxId() > dstImage.GetLastAppliedTxId())
{
FilePath f = dstStorage.FindFinalizedEditsFile(log.GetStartTxId(), log.GetEndTxId
());
editsStreams.AddItem(new EditLogFileInputStream(f, log.GetStartTxId(), log.GetEndTxId
(), true));
}
}
Log.Info("Checkpointer about to load edits from " + editsStreams.Count + " stream(s)."
);
dstImage.LoadEdits(editsStreams, dstNamesystem);
}
internal virtual void DoTailEdits()
{
// Write lock needs to be interruptible here because the
// transitionToActive RPC takes the write lock before calling
// tailer.stop() -- so if we're not interruptible, it will
// deadlock.
namesystem.WriteLockInterruptibly();
try
{
FSImage image = namesystem.GetFSImage();
long lastTxnId = image.GetLastAppliedTxId();
if (Log.IsDebugEnabled())
{
Log.Debug("lastTxnId: " + lastTxnId);
}
ICollection <EditLogInputStream> streams;
try
{
streams = editLog.SelectInputStreams(lastTxnId + 1, 0, null, false);
}
catch (IOException ioe)
{
// This is acceptable. If we try to tail edits in the middle of an edits
// log roll, i.e. the last one has been finalized but the new inprogress
// edits file hasn't been started yet.
Log.Warn("Edits tailer failed to find any streams. Will try again " + "later.", ioe
);
return;
}
if (Log.IsDebugEnabled())
{
Log.Debug("edit streams to load from: " + streams.Count);
}
// Once we have streams to load, errors encountered are legitimate cause
// for concern, so we don't catch them here. Simple errors reading from
// disk are ignored.
long editsLoaded = 0;
try
{
editsLoaded = image.LoadEdits(streams, namesystem);
}
catch (EditLogInputException elie)
{
editsLoaded = elie.GetNumEditsLoaded();
throw;
}
finally
{
if (editsLoaded > 0 || Log.IsDebugEnabled())
{
Log.Info(string.Format("Loaded %d edits starting from txid %d ", editsLoaded, lastTxnId
));
}
}
if (editsLoaded > 0)
{
lastLoadTimeMs = Time.MonotonicNow();
}
lastLoadedTxnId = image.GetLastAppliedTxId();
}
finally
{
namesystem.WriteUnlock();
}
}