RazorDB.KeyValueStore.InternalEnumerateFromKey C# (CSharp) Method

        private IEnumerable<KeyValuePair<Key, Value>> InternalEnumerateFromKey(byte[] startingKey) {

            if (startingKey == null) {
                yield break;
            }

            var enumerators = new List<IEnumerable<KeyValuePair<Key, Value>>>();
            Key key = new Key(startingKey, 0);

            // Capture copy of the rotated table if there is one
            var rotatedMemTable = _rotatedJournaledMemTable;

            // Select main MemTable
            enumerators.Add(_currentJournaledMemTable.EnumerateSnapshotFromKey(key));

            if (rotatedMemTable != null)
                enumerators.Add(rotatedMemTable.EnumerateSnapshotFromKey(key));

            // Now check the files on disk
            using (var manifestSnapshot = _manifest.GetLatestManifest()) {
                List<SortedBlockTable> pages = new List<SortedBlockTable>();
                try {
                    pages.AddRange(manifestSnapshot.GetPagesAtLevel(0)
                        .OrderByDescending(page => page.Version)
                        .Select(page => {
                            PerformanceCounters.SBTEnumerateFromKey.Increment();
                            return new SortedBlockTable(_cache, _manifest.BaseFileName, page.Level, page.Version);
                        }));
                    pages.ForEach(p => enumerators.Add(p.EnumerateFromKey(_cache, key)));

                    for (int i = 1; i < manifestSnapshot.NumLevels; i++)
                        enumerators.Add(TableEnumerator.Enumerate(i, _cache, _manifest.BaseFileName, manifestSnapshot, key));

                    foreach (var pair in MergeEnumerator.Merge(enumerators, t => t.Key))
                        yield return pair;

                } finally {
                    // make sure all the tables get closed
                    pages.ForEach(table => table.Close());
                }
            }

        }