At Tue, 14 Jan 2014 11:34:03 +0800, Liu Yuan wrote: > > On Tue, Jan 14, 2014 at 12:00:33PM +0900, Hitoshi Mitake wrote: > > > > The commit 9ea90be39e9d (sheep: use rbtree to manage struct sd_node) > > changes struct sd_node. So the master branch isn't compatible with > > v0.7.x because it affects the format of GET_NODE_LIST's returned > > buffer. Every dog command which has a flag CMD_NEED_NODELIST cannot > > work (users see nodes have IPv6 addresses). > > Why you need v0.7.x dog to communite with latest sheep? There are many problems > other than imcompatibility of struct sd_node I don't need. Communication should be forbidden. Or if it is allowed, the different format problem shuold be solved. > > > The affection is very serious so I propose either of the below two > > changes: > > serious for what usage which can't be workaround and the only solution is to > adopt following 2? I'm not saying the 2nd one is the only solution. I don't have strong opinions about this issue. Simply forbidding communication between 0.7.x dog and the latest sheep is enough. > > > 1. change protocol version and forbid communication between 0.7.x dog > > and the latest sheep > > > > 2. change struct sd_node and exclude struct rb_node rb; from the > > members > > > > I think 2 would be a better option. sd_node is a data structure which > > > can be exchanged via network and such a data structure shouldn't have > > pointers as its members. Current sd_node is really ugly. > > Talk is cheap, feel free to post a patch that fullfill current features: > 1. allow 6k+ nodes (100k+ vnodes) manage effeciently (at least don't degrade) > 2. don't break current usage (we already have a production cluster based on > current latest master, so your patch should work with current data without > re-format or any tricky upgrade. We want, at least for v0.8.x > series, we can get a smooth update for furture. OK, I'll not follow the 2nd option. > > There are many ugliness in sheep and also many existing problems. My advice is > solve problems at first and don't invest time on something that changing core > code just for something you think of beatiful. Chanign coring is always at risk > to introduce new bugs and need time to stablize. I introduce rb_tree to manage > vnodes because we have to use it to manage more than 10 thousands of vnodes, which > old array approach can't handle well. So what is your motivation besides 'ugliness'? Generally speaking, data structures which can be sent/recv network shouldn't contain pointers. That's all. Do you agree with incrementing protocol version? Thanks, Hitoshi |