Brice -- > This is a rather complex set of structural changes. But to understand it > you > > really only need to grasp two key sections; the rest is cleanup. > > Can you explain for people like me that didn't had time to try to > understand the patch what it brings, how (roughly) the internals > changed, and why it was needed? > That'd be terrific (and in the meantime I promise I'll read the patch). >
Sure. Here's a rundown of the "features" that result: 1) Stable ordering. Changes in the definition or application of a resource now will not change the ordering of any other pair of resources (apart from changes that may be forced by new dependencies). This eliminates post deployment reordering of resource application; which means that catalogs that worked in testing should work "the same way" when pushed to production. 2) Sententials. We're preparing some graphics to make this clearer, but it's not to bad in words. Instead of replacing containers with an edge from each of the content nodes to all of the dependencies (which is a multiplicative explosion with sibling containers and an exponential one with nested containers) we replace them with a pair (think of open/close brackets) which drastically reduces the "edge explosion" with nested classes, stages, etc. This caused puppet to suck up all available ram and peg the cpu on certain loads, and it won't do that anymore. 3) Frontiers. By dynamically determining the application order and eliminating the topological sort we enable all sorts of dependency-aware features (sub-states, external dependencies, eventual parallelism, etc.). In the process we cleaned up a number of subtle ordering bugs and created the opportunity for more fixes on future passes. -- M ----------------------------------------------------------- When in trouble or in doubt, run in circles, scream and shout. -- 1920's parody of the maritime general prudential rule ------------------------------------------------------------ -- You received this message because you are subscribed to the Google Groups "Puppet Developers" group. To post to this group, send email to puppet-dev@googlegroups.com. To unsubscribe from this group, send email to puppet-dev+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/puppet-dev?hl=en.
