Michi -- On Nov 5, 2012, at 11:24 PM, Michi Mutsuzaki <mi...@cs.stanford.edu> wrote:
> On Mon, Nov 5, 2012 at 2:16 PM, Yunong Xiao <yjx...@gmail.com> wrote: >> What happens if the server is offline? In the scenario you described, >> select() >> will never succeed, and zookeeper_interest() will never inform the upstream >> consumer that the server is down. That's the crux of the problem here, when >> the >> server is unavailable, the client needs to know after some amount of time >> that >> the connection has failed. Otherwise the upstream consumer has no idea the >> connection to zookeeper has been severed and will hang indefinitely. > > If the server is offline, zookeeper client keeps trying to connect to > the server indefinitely. It's up to the caller to decide when to give > up. One possibility is to poll the connection state using zoo_state() > and give up on the handle if it doesn't become connected after certain > time. I certainly don't disagree here. What you're suggesting makes sense here -- indeed my patch does a variation of this -- however, it relies on the consuming client to keep track of the time since the client was last connected to the server. I dare say it'd be more preferable for zookeeper.c to keep track of this time internally, and inform the consuming client when this time has exceeded a certain threshold, such as session_timeout. The consuming client can then decide to give up. It seems like common functionality that all consumers would like to have as part of using the C client.
