internal bool Run()
{
if (_keyValueDB.FileCollection.GetCount() == 0)
{
return(false);
}
_root = _keyValueDB.LastCommited;
var dontTouchGeneration = _keyValueDB.GetGeneration(_root.TrLogFileId);
InitFileStats(dontTouchGeneration);
CalculateFileUsefullness();
var totalWaste = CalcTotalWaste();
if (totalWaste < (ulong)_keyValueDB.MaxTrLogFileSize / 4)
{
if (_keyValueDB.DistanceFromLastKeyIndex(_root) < (ulong)(_keyValueDB.MaxTrLogFileSize / 4))
{
return(false);
}
_keyValueDB.CreateIndexFile(_cancellation);
_keyValueDB.FileCollection.DeleteAllUnknownFiles();
return(false);
}
_cancellation.ThrowIfCancellationRequested();
uint valueFileId;
var writer = _keyValueDB.StartPureValuesFile(out valueFileId);
_newPositionMap = new Dictionary <ulong, uint>();
var toRemoveFileIds = new List <uint>();
while (true)
{
var wastefullFileId = FindMostWastefullFile(_keyValueDB.MaxTrLogFileSize - writer.GetCurrentPosition());
if (wastefullFileId == 0)
{
break;
}
MoveValuesContent(writer, wastefullFileId);
_fileStats[wastefullFileId] = new FileStat(0);
toRemoveFileIds.Add(wastefullFileId);
}
var valueFile = _keyValueDB.FileCollection.GetFile(valueFileId);
valueFile.HardFlush();
valueFile.Truncate();
var btreesCorrectInTransactionId = _keyValueDB.AtomicallyChangeBTree(root => root.RemappingIterate((uint oldFileId, uint oldOffset, out uint newFileId, out uint newOffset) =>
{
newFileId = valueFileId;
_cancellation.ThrowIfCancellationRequested();
return(_newPositionMap.TryGetValue(((ulong)oldFileId << 32) | oldOffset, out newOffset));
}));
_keyValueDB.CreateIndexFile(_cancellation);
_keyValueDB.WaitForFinishingTransactionsBefore(btreesCorrectInTransactionId, _cancellation);
if (_newPositionMap.Count == 0)
{
toRemoveFileIds.Add(valueFileId);
}
_keyValueDB.MarkAsUnknown(toRemoveFileIds);
_keyValueDB.FileCollection.DeleteAllUnknownFiles();
return(true);
}
