Interesing “feature” of the Mediawiki
Just have a bit digged in the Mediawiki, that is quite popular Wiki engine :-) Found out that the articles are located in the “prefix_text” table, with all the changes, obviously. So changes are being stored as a new copy of the article: if you have 100kb article and you need to save a change in 1 symbol, there would be 100kb growth (plus additional data) of the table. No wonder that the Wikipedia need new servers all the time! Cannot imagine size of their DBs.