Board Thread:New Features/@comment--20170713212413/@comment-1077307-20170820012411

FYI, I think I found a somewhat serious but possibly unintended performance issue with Wikia Scribuno and mw.loadData.

When mw.loadData is used, the general intent seems to be to have one load per module per wiki page. However because of the blind root-level clone when the MediaWiki code is hoisting up a new sub-environment all of the data through loadData is appears to get copied again for every sub-environment load, via the careful but slow Lua-side clone function.

In my test so far, the natural Lua literal table load appears to beat the clone by about 2 or 3 to 1, in performance and sometimes memory, so the CommonData DB wont be using any calls mw.loadData for the time being.

Just a heads up.