Platonides,
Why do you need eg. the initial phase of copying the links from language database into memory tables (page links, category links, template links, zero namespace pages, category pages, template pages) ?
Connectivity is a property of a graph as a whole, there is no way to analyze it having just a part of all nodes and edges. Use of original tables in language database or use of MyISAM tables makes the analysis far too slow. Good thing with memory tables is not only in being located in memory (which is not always true of course), the engine is optimized for speed itself and the format is designed to allow that.
mashiah