public bool TryGet(Slice key, ulong seq, ReadOptions readOptions, out Stream stream, out GetStats stats)
{
stats = new GetStats
{
SeekFile = null,
SeekFileLevel = -1
};
FileMetadata lastFileRead = null;
int lastFileReadLevel = -1;
var internalKey = new InternalKey(key, seq, ItemType.ValueForSeek);
// We can search level-by-level since entries never hop across
// levels. Therefore we are guaranteed that if we find data
// in an smaller level, later levels are irrelevant.
for (var level = 0; level < Config.NumberOfLevels; level++)
{
if (Files[level].Count == 0)
{
continue;
}
// Get the list of files to search in this level
var files = GetRelevantFilesForLevel(level, internalKey);
if (files == null || files.Count == 0)
continue;
foreach (var f in files)
{
if (lastFileRead != null && stats.SeekFile == null)
{
// We have had more than one seek for this read. Charge the 1st file.
stats.SeekFile = lastFileRead;
stats.SeekFileLevel = lastFileReadLevel;
}
lastFileRead = f;
lastFileReadLevel = level;
var state = storageContext.TableCache.Get(
internalKey,
f.FileNumber,
f.FileSize,
readOptions,
storageContext.InternalKeyComparator.UserComparator,
out stream);
switch (state)
{
case ItemState.Found:
return true;
case ItemState.NotFound:
break;
case ItemState.Deleted:
return false;
case ItemState.Corrupt:
return false;
default:
throw new NotSupportedException(state.ToString());
}
}
}
stream = null;
return false;
}
public bool UpdateStats(GetStats stats)
{
var file = stats.SeekFile;
if (file != null)
{
file.AllowedSeeks--;
if (file.AllowedSeeks <= 0 && FileToCompact == null)
{
FileToCompact = file;
FileToCompactLevel = stats.SeekFileLevel;
}
}
return false;
}
