Thank you Alexander. I get it Ibrahim From: Alexander Shraer-2 [via zookeeper-user] [mailto:ml-node+s578899n7580745h19@n2.nabble.com] Sent: Wednesday, January 07, 2015 12:29 ص To: Ibrahim El-sanosi (PGR) Subject: Re: Question about the two-phrase commit Edward is totally right - if the operation hasn't been acked by a quorum then whether or not it is lost depends on failures (both server failures and network failures) as well as latencies. The leader doesn't have to re-broadcast everything - when a follower connects to a leader it tells him whats the last operation in its log and the leader only needs to send the missing log suffix or a snapshot + suffix if the follower is really behind. The leader indeed doesn't know which operations were acked by a quorum. The operations that weren't acked are always some suffix of the log (potentially empty). On Tue, Jan 6, 2015 at 4:19 PM, Ibrahim <[hidden email]> wrote: > Thank you Edward for replaying. > > In my opinion, your first case can’t happen, because the election > mechanism will elect the node that has the latest transaction (zxid) seen. > In this case, it will be only your second case is correct, unless the node > that has latest transaction crashes forever. > > Ibrahim > From: Edward Carter [via zookeeper-user] [mailto: > [hidden email]] > Sent: Tuesday, January 06, 2015 11:53 م > To: Ibrahim El-sanosi (PGR) > Subject: Re: Question about the two-phrase commit > > If an operation is logged to disk on a minority of servers, then what > happens on restart depends on which server wins the leader election. Since > the new operation is on a minority, depending on network conditions, a > server that did *not* log the operation might win the leader election. In > this case, the operation will be discarded. If a server that *did* log the > operation wins the leader election (as would be the case in the absence of > network or latency issues), then the operation will be propagated to the > remaining servers in the ensemble. > > Edward > > On Jan 6, 2015, at 3:42 PM, Ibrahim <[hidden > email]> wrote: > > > Hi Alexander, > > > > So, you meant that if there is operation loged to the disk but it hasn't > got > > enough majority, then if the zookeeper servers restart, the new leader > will > > re-broadcast the loged operation again to the followers to commit that > > operation. > > > > Does above what you meant by (NEWLEADER message acts as the accept and > > UPTODATE message acts as commit). > > > > Am I right? > > > > Thank you > > > > Ibrahim > > > > > > > > -- > > View this message in context: > https://urldefense.proofpoint.com/v1/url?u=http://zookeeper-user.578899.n2.nabble.com/Question-about-the-two-phrase-commit-tp7580725p7580739.html&k=ZVNjlDMF0FElm4dQtryO4A%3D%3D%0A&r=09h%2FR60Z1NzKuJcTv9DkEw%3D%3D%0A&m=T7mEM8unY7tsVTbHXoSOqvwXEZEBCs8%2BRWl0cT03ruo%3D%0A&s=bcce5c88300c51126777473143b3f560542cf1c5699b33283f888e27ed41529f > > Sent from the zookeeper-user mailing list archive at Nabble.com. > > > ________________________________ > If you reply to this email, your message will be added to the discussion > below: > > http://zookeeper-user.578899.n2.nabble.com/Question-about-the-two-phrase-commit-tp7580725p7580741.html > To unsubscribe from Question about the two-phrase commit, click here< > >. > NAML< > http://zookeeper-user.578899.n2.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml > > > > > > > -- > View this message in context: > http://zookeeper-user.578899.n2.nabble.com/Question-about-the-two-phrase-commit-tp7580725p7580743.html > Sent from the zookeeper-user mailing list archive at Nabble.com. > ________________________________ If you reply to this email, your message will be added to the discussion below: http://zookeeper-user.578899.n2.nabble.com/Question-about-the-two-phrase-commit-tp7580725p7580745.html To unsubscribe from Question about the two-phrase commit, click here. NAML -- View this message in context: http://zookeeper-user.578899.n2.nabble.com/Question-about-the-two-phrase-commit-tp7580725p7580746.html Sent from the zookeeper-user mailing list archive at Nabble.com.