public void MaybeAddFile(InternalKey key, IIterator iterator, CompactionState compactionState, AsyncLock.LockScope locker, ref Slice lastKey, ref ulong lastSequence)
{
var drop = false;
if (lastKey.IsEmpty()
|| state.InternalKeyComparator.UserComparator.Compare(key.UserKey, lastKey) != 0)
{
// First occurrence of this user key
lastKey = key.UserKey.Clone();
lastSequence = Format.MaxSequenceNumber;
}
if (lastSequence <= compactionState.SmallestSnapshot)
{
// Hidden by an newer entry for same user key
drop = true;
}
else if (key.Type == ItemType.Deletion && key.Sequence <= compactionState.SmallestSnapshot
&& compactionState.Compaction.IsBaseLevelForKey(key.UserKey))
{
// For this user key:
// (1) there is no data in higher levels
// (2) data in lower levels will have larger sequence numbers
// (3) data in layers that are being compacted here and have
// smaller sequence numbers will be dropped in the next
// few iterations of this loop (by rule (A) above).
// Therefore this deletion marker is obsolete and can be dropped.
drop = true;
}
lastSequence = key.Sequence;
if (!drop)
{
if (compactionState.Builder == null)
{
using (locker.LockAsync().Result)
OpenCompactionOutputFileIfNecessary(compactionState, locker);
}
Debug.Assert(compactionState.Builder != null);
if (compactionState.Builder.NumEntries == 0)
compactionState.CurrentOutput.SmallestKey = new InternalKey(key.TheInternalKey.Clone());
compactionState.CurrentOutput.LargestKey = new InternalKey(key.TheInternalKey.Clone());
//Console.WriteLine("Adding " + compactionState.CurrentOutput.LargestKey);
using (var stream = iterator.CreateValueStream())
compactionState.Builder.Add(key.TheInternalKey, stream);
FinishCompactionOutputFileIfNecessary(compactionState, iterator);
}
}
