Topic on User talk:Daniel Kinzler (WMDE)/DependencyEngine

changeprop does that to some extent, it's just not very well integrated with MediaWiki.

ChangeProp is actually a little bit different thing.

For tracking the dependency graph it relies on MediaWiki and fetches the dependencies from the the link tables. The role of the changeprop is more an update scheduler then dependency tracking.

Also, if I understand the "popDirty" proposal correctly, it implies a pop-based approach, something like what's currently implemented in the Redis-based Job Queue and the job runner service. Recent issues with the job queue show that this type of scheduling is hard to do right (all the examples when unbounded growth of backlog on a single project was affecting other projects and wasn't easy to solve even by incrementing the number of runners for that particular wiki). ChangeProp uses push-based approach when the updates are done in order they arrive strictly sequentially, possibly partitioned by wiki or a DB shard.

@Pchelolo I meant that ChangeProp has its own built-in dependency graph in the form of rules.