Really nice presentation. 2013/4/17 Mark Miller <markrmil...@gmail.com>
> > On Apr 16, 2013, at 1:36 AM, SuoNayi <suonayi2...@163.com> wrote: > > > Hi, can someone explain more details about what model is used to sync > docs between the lead and > > replica in the shard? > > The model can be push or pull.Supposing I have only one shard that has 1 > leader and 2 replicas, > > when the leader receives a update request, does it will scatter the > request to each available and active > > replica at first and then processes the request locally at last?In this > case if the replicas are able to catch > > up with the leader can I think this is a push model that the leader > pushes updates to it's replicas? > > Currently, the leader adds the doc locally and then sends it to all > replicas concurrently. > > > > > > > What happens if a replica is behind the leader?Will the replica pull > docs from the leader and keep > > a track of the coming updates from the lead in a log(called tlog)?If so > when it complete pulling docs > > it will replay updates in the tlog at last? > > If an update forwarded from a leader to a replica fails it's likely > because that replica died. Just in case, the leader will ask that replica > to enter "recovery". > > When a node comes up and is not a leader, it also enters "recovery". > > Recovery tries to peersync from the leader, and if that fails (works if > off by about 100 updates), it replicates the entire index. > > If you are interested in more details on the SolrCloud architecture, I've > given a few talks on it - two of them here: > > http://vimeo.com/43913870 > http://www.youtube.com/watch?v=eVK0wLkLw9w > > - Mark > >
