private void FinishCompactionOutputFileIfNecessary(CompactionState compactionState, IIterator input, bool force = false)
{
if (compactionState.Builder == null)
return;
// Finish when:
// 1. When close output file is big enough
// 2. When we should stop before input key
// 3. When forced
if (compactionState.Builder.FileSize < compactionState.Compaction.MaxOutputFileSize
&& force == false
&& (input.IsValid == false || !compactionState.Compaction.ShouldStopBefore(input.Key)))
return;
//Console.WriteLine("Finishing");
var outputNumber = compactionState.CurrentOutput.FileNumber;
Debug.Assert(outputNumber != 0);
var currentEntries = compactionState.Builder.NumEntries;
compactionState.Builder.Finish();
var currentBytes = compactionState.Builder.FileSize;
compactionState.CurrentOutput.FileSize = currentBytes;
compactionState.TotalBytes += currentBytes;
compactionState.Builder.Dispose();
compactionState.Builder = null;
if (currentEntries <= 0)
return;
if (state.Options.ParanoidChecks)
using (this.state.TableCache.NewIterator(new ReadOptions(), outputNumber, currentBytes))
{
// Verify that the table is usable
}
}
private async Task BackgroundCompactionAsync(AsyncLock.LockScope locker)
{
state.CancellationToken.ThrowIfCancellationRequested();
if (state.ImmutableMemTable != null)
{
await CompactMemTableAsync(locker).ConfigureAwait(false);
}
var compaction = CompactionToProcess();
if (compaction == null)
{
return;
}
if (IsManual == false && compaction.IsTrivialMove())
{
Debug.Assert(compaction.GetNumberOfInputFiles(0) == 1);
var file = compaction.GetInput(0, 0);
compaction.Edit.DeleteFile(compaction.Level, file.FileNumber);
compaction.Edit.AddFile(compaction.Level + 1, file);
await state.LogAndApplyAsync(compaction.Edit, locker).ConfigureAwait(false);
log.Info("Moved {0} to level-{1} {2} bytes", file.FileNumber, compaction.Level + 1, file.FileSize);
}
else
{
using (var compactionState = new CompactionState(compaction))
{
try
{
await DoCompactionWorkAsync(compactionState, locker).ConfigureAwait(false);
}
finally
{
CleanupCompaction(compactionState);
}
}
compaction.ReleaseInputs();
DeleteObsoleteFiles();
}
}
private void OpenCompactionOutputFileIfNecessary(CompactionState compactionState, AsyncLock.LockScope locker)
{
if (compactionState.Builder != null)
return;
Debug.Assert(locker.Locked);
var fileNumber = this.state.VersionSet.NewFileNumber();
pendingOutputs.Add(fileNumber);
compactionState.AddOutput(fileNumber);
locker.Exit();
// make the output file
var fileName = state.FileSystem.GetTableFileName(fileNumber);
var file = state.FileSystem.NewWritable(fileName);
compactionState.Builder = new TableBuilder(state, file, new TemporaryFiles(state.FileSystem, fileNumber));
}
private async Task InstallCompactionResultsAsync(CompactionState compactionState, AsyncLock.LockScope locker)
{
log.Info("Compacted {0}@{1} + {2}@{3} files => {4} bytes", compactionState.Compaction.GetNumberOfInputFiles(0), compactionState.Compaction.Level, compactionState.Compaction.GetNumberOfInputFiles(1), compactionState.Compaction.Level + 1, compactionState.TotalBytes);
compactionState.Compaction.AddInputDeletions(compactionState.Compaction.Edit);
var level = compactionState.Compaction.Level;
foreach (var output in compactionState.Outputs)
compactionState.Compaction.Edit.AddFile(level + 1, output);
await state.LogAndApplyAsync(compactionState.Compaction.Edit, locker).ConfigureAwait(false);
}
private IIterator CreateInputIterator(CompactionState compactionState)
{
var readOptions = new ReadOptions
{
VerifyChecksums = state.Options.ParanoidChecks,
FillCache = false
};
return new MergingIterator(state.InternalKeyComparator, compactionState.Compaction.Inputs[0].Select(x => state.TableCache.NewIterator(readOptions, x.FileNumber, x.FileSize)).ToList());
}
private void CreateCompactionStats(CompactionState compactionState, Stopwatch watch)
{
var stats = new CompactionStats { Milliseconds = watch.ElapsedMilliseconds };
for (var which = 0; which < 2; which++)
{
for (var i = 0; i < compactionState.Compaction.GetNumberOfInputFiles(which); i++)
{
stats.BytesRead += compactionState.Compaction.GetInput(which, i).FileSize;
}
}
foreach (var output in compactionState.Outputs)
{
stats.BytesWritten += output.FileSize;
}
state.CompactionStats[compactionState.Compaction.Level + 1].Add(stats);
}
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);
}
}
private void CleanupIfNecessary(InternalKey key, CompactionState compactionState, IIterator iterator, IDictionary<FileMetadata, bool> destinationFiles)
{
var filesToRemove = new List<KeyValuePair<FileMetadata, bool>>();
foreach (var pair in destinationFiles)
{
var r = state.InternalKeyComparator.UserComparator.Compare(key.UserKey, pair.Key.LargestKey.UserKey);
if (r > 0)
{
// past the file
filesToRemove.Add(pair);
}
else if (r < 0)
{
// past the file - no need to check further
break;
}
}
if (filesToRemove.Count == 0)
return;
foreach (var pair in filesToRemove)
{
destinationFiles.Remove(pair);
if (pair.Value)
compactionState.Compaction.Inputs[1].Remove(pair.Key);
}
if (filesToRemove.Any(x => x.Value))
FinishCompactionOutputFileIfNecessary(compactionState, iterator, true);
}
private async Task PerformRapidCompactionAsync(CompactionState compactionState, Stopwatch watch, AsyncLock.LockScope locker)
{
using (var source = CreateInputIterator(compactionState))
{
InternalKey sourceInternalKey = new InternalKey();
InternalKey fileInternalKey;
FileMetadata file = null;
IIterator fileIterator = null;
Slice lastKey = null;
ulong lastSequence = 0;
bool addSource = true;
try
{
var destinationFiles = compactionState.Compaction.Inputs[1].ToDictionary(x => x, x => true);
source.SeekToFirst();
while (source.IsValid)
{
if (state.ImmutableMemTable != null)
await CompactMemTableAsync(locker).ConfigureAwait(false);
state.CancellationToken.ThrowIfCancellationRequested();
if (addSource && !InternalKey.TryParse(source.Key, out sourceInternalKey))
throw new InvalidOperationException("Source key must be a valid internal key.");
addSource = false;
if (destinationFiles.Count > 0 && file == null)
{
file = PickOverlapingFile(sourceInternalKey, destinationFiles);
CleanupIfNecessary(sourceInternalKey, compactionState, null, destinationFiles);
}
if (file != null && fileIterator == null)
{
fileIterator = CreateFileIterator(file);
fileIterator.SeekToFirst();
}
if (fileIterator != null)
{
while (fileIterator.IsValid)
{
if (!InternalKey.TryParse(fileIterator.Key, out fileInternalKey))
throw new InvalidOperationException("File key must be a valid internal key.");
if (state.InternalKeyComparator.Compare(sourceInternalKey, fileInternalKey) <= 0)
{
addSource = true;
break;
}
MaybeAddFile(fileInternalKey, source, compactionState, locker, ref lastKey, ref lastSequence);
fileIterator.Next();
}
if (!fileIterator.IsValid)
{
file = null;
fileIterator.Dispose();
fileIterator = null;
}
}
else
{
addSource = true;
}
if (!addSource)
continue;
MaybeAddFile(sourceInternalKey, source, compactionState, locker, ref lastKey, ref lastSequence);
source.Next();
}
if (fileIterator != null)
{
while (fileIterator.IsValid)
{
if (!InternalKey.TryParse(fileIterator.Key, out fileInternalKey))
throw new InvalidOperationException("File key must be a valid internal key.");
MaybeAddFile(fileInternalKey, fileIterator, compactionState, locker, ref lastKey, ref lastSequence);
fileIterator.Next();
}
}
if (sourceInternalKey.UserKey.IsEmpty() == false)
CleanupIfNecessary(sourceInternalKey, compactionState, null, destinationFiles);
}
finally
{
if (fileIterator != null)
fileIterator.Dispose();
}
FinishCompactionOutputFileIfNecessary(compactionState, source, force: true);
CreateCompactionStats(compactionState, watch);
await InstallCompactionResultsAsync(compactionState, locker).ConfigureAwait(false);
}
}
private async Task DoCompactionWorkAsync(CompactionState compactionState, AsyncLock.LockScope locker)
{
var watch = Stopwatch.StartNew();
using (await locker.LockAsync())
{
log.Info("Compacting {0}@{1} + {2}@{3} files.", compactionState.Compaction.GetNumberOfInputFiles(0), compactionState.Compaction.Level, compactionState.Compaction.GetNumberOfInputFiles(1), compactionState.Compaction.Level + 1);
Debug.Assert(state.VersionSet.GetNumberOfFilesAtLevel(compactionState.Compaction.Level) > 0);
Debug.Assert(compactionState.Builder == null);
compactionState.SmallestSnapshot = state.Snapshooter.Snapshots.Count == 0 ? state.VersionSet.LastSequence : state.Snapshooter.Snapshots.First().Sequence;
}
Slice currentUserKey = null;
var lastSequenceForKey = Format.MaxSequenceNumber;
state.CancellationToken.ThrowIfCancellationRequested();
await PerformRapidCompactionAsync(compactionState, watch, locker);
return;
using (IIterator input = state.VersionSet.MakeInputIterator(compactionState.Compaction))
{
input.SeekToFirst();
while (input.IsValid)
{
if (state.ImmutableMemTable != null)
await CompactMemTableAsync(locker).ConfigureAwait(false);
state.CancellationToken.ThrowIfCancellationRequested();
var key = input.Key;
FinishCompactionOutputFileIfNecessary(compactionState, input);
InternalKey internalKey;
if (!InternalKey.TryParse(key, out internalKey))
{
currentUserKey = null;
lastSequenceForKey = Format.MaxSequenceNumber;
input.Next();
continue;
}
var drop = false;
if (currentUserKey.IsEmpty()
|| state.InternalKeyComparator.UserComparator.Compare(internalKey.UserKey, currentUserKey) != 0)
{
// First occurrence of this user key
currentUserKey = internalKey.UserKey.Clone();
lastSequenceForKey = Format.MaxSequenceNumber;
}
if (lastSequenceForKey <= compactionState.SmallestSnapshot)
{
// Hidden by an newer entry for same user key
drop = true;
}
else if (internalKey.Type == ItemType.Deletion && internalKey.Sequence <= compactionState.SmallestSnapshot
&& compactionState.Compaction.IsBaseLevelForKey(internalKey.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;
}
lastSequenceForKey = internalKey.Sequence;
if (!drop)
{
if (compactionState.Builder == null)
{
using (await locker.LockAsync())
OpenCompactionOutputFileIfNecessary(compactionState, locker);
}
Debug.Assert(compactionState.Builder != null);
if (compactionState.Builder.NumEntries == 0)
compactionState.CurrentOutput.SmallestKey = new InternalKey(key.Clone());
compactionState.CurrentOutput.LargestKey = new InternalKey(key.Clone());
using (var stream = input.CreateValueStream())
compactionState.Builder.Add(key, stream);
FinishCompactionOutputFileIfNecessary(compactionState, input);
}
input.Next();
}
FinishCompactionOutputFileIfNecessary(compactionState, input, force: true);
}
CreateCompactionStats(compactionState, watch);
await InstallCompactionResultsAsync(compactionState, locker).ConfigureAwait(false);
}
private void CleanupCompaction(CompactionState compactionState)
{
foreach (var output in compactionState.Outputs)
{
pendingOutputs.Remove(output.FileNumber);
}
}