Cluster: new clusterDoBeforeSleep() API.
The new API is able to remember operations to perform before returning to the event loop, such as checking if there is the failover quorum for a slave, save and fsync the configuraiton file, and so forth. Because this operations are performed before returning on the event loop we are sure that messages that are sent in the same event loop run will be delivered *after* the configuration is already saved, that is a requirement sometimes. For instance we want to publish a new epoch only when it is already stored in nodes.conf in order to avoid returning back in the logical clock when a node is restarted. This new API provides a big performance advantage compared to saving and possibly fsyncing the configuration file multiple times in the same event loop run, especially in the case of big clusters with tens or hundreds of nodes.
Showing
想要评论请 注册 或 登录