expiry: one hour
Difference Engine:
- key: $wgDBname:diff:version:{DifferenceEngine::CACHE_VERSION}:oldid:$old:newid:$new
+ key: $wgDBname:diff:version:{MW_DIFF_VERSION}:oldid:$old:newid:$new
ex: wikidb:diff:version:1.11a:oldid:1:newid:2
stores: body of a difference
cleared by: nothing