예제 #1
0
        /// <summary>
        /// Get journal pages and override all into datafile
        /// </summary>
        public void Recovery()
        {
            _log.Write(Logger.Recovery, "initializing recovery mode");

            using (_locker.Write())
            {
                // double check in header need recovery (could be already recover from another thread)
                var header = BasePage.ReadPage(_disk.ReadPage(0)) as HeaderPage;

                if (header.Recovery == false)
                {
                    return;
                }

                // read all journal pages
                foreach (var buffer in _disk.ReadJournal(header.LastPageID))
                {
                    // read pageID (first 4 bytes)
                    var pageID = BitConverter.ToUInt32(buffer, 0);

                    _log.Write(Logger.Recovery, "recover page #{0:0000}", pageID);

                    // write in stream (encrypt if datafile is encrypted)
                    _disk.WritePage(pageID, _crypto == null || pageID == 0 ? buffer : _crypto.Encrypt(buffer));
                }

                // shrink datafile
                _disk.ClearJournal(header.LastPageID);
            }
        }
예제 #2
0
        /// <summary>
        /// Encapsulate all operations in a single write transaction
        /// </summary>
        private T Transaction <T>(string collection, bool addIfNotExists, Func <CollectionPage, T> action)
        {
            // always starts write operation locking database
            using (_locker.Write())
            {
                try
                {
                    var col = GetCollectionPage(collection, addIfNotExists);

                    var result = action(col);

                    _trans.PersistDirtyPages();

                    return(result);
                }
                catch (Exception ex)
                {
                    _log.Write(Logger.Error, ex.Message);

                    // if an error occurs during an operation, rollback must be called to avoid datafile inconsistent
                    _cache.DiscardDirtyPages();

                    throw;
                }
            }
        }