public EventStream(StreamOptions options)
{
_options = options;
_options.Initialize();
_currentBufferSize = _options.InitialInMemoryBuffer;
long log;
_memTable = new MemRange
{
MemTable = new MemTable(_currentBufferSize, new InternalKeyComparator(options.Comparator), _options.BufferPool),
Start = EtagToSlice(Etag.Empty),
Log = new LogWriter(_options.CreateNewLogFile(out log), _options.BufferPool),
LogNumber = log
};
}
private void WriteMemTableToDisk(MemRange range)
{
string fileName;
Slice first = new Slice(), last = new Slice();
using (var stream = _options.CreateNewTableFile(out fileName))
using (var builder = new TableBuilder(_options, stream, _options.Storage.CreateTemp))
using (var it = range.MemTable.NewIterator())
{
it.SeekToFirst();
while (it.IsValid)
{
if (first.Array == null)
first = it.Key;
last = it.Key;
using (var valueStream = it.CreateValueStream())
builder.Add(it.Key, valueStream);
it.Next();
}
builder.Finish();
_options.Storage.Flush(stream);
}
lock (_metadataLocker)
{
_options.Status.Ranges = new List<CurrentStatus.SstRange>(_options.Status.Ranges)
{
new CurrentStatus.SstRange
{
End = last,
Name = fileName,
Start = first,
Count = range.MemTable.Count
}
};
_options.Status.LastCompletedLog = range.LogNumber;
_options.FlushStatus();
}
}
// REQUIRE: no other concurrent access to the event stream
public async Task FlushMemTableToFiskAsync(Etag newEtag)
{
if (_flushingMemTable != null)
{
// we are currently writing this to disk, let us wait for that
try
{
await _flushingMemTable;
}
finally
{
_flushingMemTable = null;
_immutableMemTable = null;
}
}
if (_memTable.MemTable.Count == 0)
{
return;
}
var imm = _memTable;
_flushingMemTable = Task.Factory.StartNew(() => WriteMemTableToDisk(imm));
lock (_metadataLocker)
{
_immutableMemTable = _memTable;
_flushingMemTable = _flushingMemTable.ContinueWith(task =>
{
using (imm)
{
_immutableMemTable = null;
}
});
long log;
_memTable = new MemRange
{
MemTable = new MemTable(_currentBufferSize, new InternalKeyComparator(_options.Comparator), _options.BufferPool),
Start = EtagToSlice(newEtag),
Log = new LogWriter(_options.CreateNewLogFile(out log), _options.BufferPool),
LogNumber = log
};
}
}
