What could cause this behavior and how should I configure my system to prevent the deadlocks? If this is a Bug in either MediWiki or the VisualEditor or Parsoid, how to further investigate and fix it? Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
Holding a database lock while a Parsoid query is made seems like a really bad idea. That seems like it could be a big in MediaWiki core. However, I'm running an almost identical setup on my machine (Debian/unstable rather than wheezy) as are most Parsoid developers (Ubuntu instead of Debian) and I've never seen this.
Perhaps I might suggest looking closely at the code which takes database locks, and why it is doing so? Perhaps more details on your db configuration would also be helpful, if you're not using Debian and MediaWiki defaults. --scott