The subject technology performs a search for a key in a regular space to locate a first visible version of the key. The subject technology determines that the first visible version of the key is not one of a N number of newest versions of the key. The subject technology performs a search of an undo space to locate a second visible version of the key. The subject technology determines whether the first visible version or the second visible version of the key is newer. The subject technology provides a newer version of the key between the first visible version and the second visible version of the key.