void StartNewHashIndexFile()
{
_hashIndexFile = _fileCollection.AddFile("hid");
_hashIndexWriter = _hashIndexFile.GetAppenderWriter();
var fileInfo = new HashKeyIndex(_subDBId, _fileCollection.NextGeneration(), _fileCollection.Guid, (uint)_keyLen);
fileInfo.WriteHeader(_hashIndexWriter);
_fileCollection.SetInfo(_hashIndexFile.Index, fileInfo);
}