/// <summary> /// Dispose stream readers and exit collection lock /// </summary> public void Dispose() { // release all data/index pages this.Clear(); // release collection page (in read mode) if (_mode == LockMode.Read && _collectionPage != null) { _collectionPage.Buffer.Release(); } if (_mode == LockMode.Read) { _locker.ExitRead(_collectionName); } else if (_mode == LockMode.Write) { _locker.ExitReserved(_collectionName); } }
/// <summary> /// Do checkpoint operation to copy log pages into data file. Return how many transactions was commited inside data file /// If soft = true, just try enter in exclusive mode - if not possible, just exit /// </summary> public void Checkpoint(bool soft) { // get original log length var logLength = _disk.GetLength(FileOrigin.Log); // no log file or no confirmed transaction, just exit if (logLength == 0 || _confirmTransactions.Count == 0) { return; } // for safe, lock all database (read/write) before run checkpoint operation // future versions can be smarter and avoid lock (be more like SQLite checkpoint) if (soft) { // shutdown mode only try enter in exclusive mode... if not possible, exit without checkpoint if (_locker.TryEnterExclusive() == false) { return; } } else { _locker.EnterReserved(true); } LOG($"checkpoint", "WAL"); // wait all pages write on disk _disk.Queue.Wait(); ENSURE(_disk.Queue.Length == 0, "no pages on queue when checkpoint"); // getting all "good" pages from log file to be copied into data file IEnumerable <PageBuffer> source() { foreach (var buffer in _disk.ReadFull(FileOrigin.Log)) { // read direct from buffer to avoid create BasePage structure var transactionID = buffer.ReadUInt32(BasePage.P_TRANSACTION_ID); // only confied paged can be write on data disk if (_confirmTransactions.Contains(transactionID)) { var pageID = buffer.ReadUInt32(BasePage.P_PAGE_ID); // clear isConfirmed/transactionID buffer.Write(uint.MaxValue, BasePage.P_TRANSACTION_ID); buffer.Write(false, BasePage.P_IS_CONFIRMED); buffer.Position = BasePage.GetPagePosition(pageID); yield return(buffer); } } } // write all log pages into data file (sync) _disk.Write(source(), FileOrigin.Data); // reset _confirmTransactions.Clear(); _index.Clear(); _currentReadVersion = 0; // clear cache _disk.Cache.Clear(); // clear log file (sync) _disk.SetLength(0, FileOrigin.Log); // remove exclusive lock _locker.ExitReserved(true); }