2) Applied the same approach to temporary GC records.
3) Refactored the Record class to avoid reallocations, to improve encapsulation and to simplify the code.
4) Slightly refactored UndoItem to isolate its logic from the Record class.
5) Reduced the in-memory size of the undo log.
6) Slightly better alternative to the legacy NULL reporting for outer joins.
7) Minor fixes and adjustments in BufferedStream.