Message ID does not have to be sequential for our use cases. Just a UUID would do.
On Fri, Jul 12, 2013 at 2:08 PM, Srinath Perera <srin...@wso2.com> wrote: > Hazecast has an atomic Long ( > http://www.hazelcast.com/javadoc/com/hazelcast/core/AtomicNumber.html) we > can use that as the messageID and that way we can detect all missing > messages as Suho mentioned (need to check the performance though) > > --Srinath > > > On Sun, Jul 7, 2013 at 2:53 PM, Sriskandarajah Suhothayan > <s...@wso2.com>wrote: > >> >> >> On Sat, Jul 6, 2013 at 2:56 PM, Supun Malinga <sup...@wso2.com> wrote: >> >>> Hi Azeez, >>> >>> Totally +1 for the approach. >>> I can suggest some improvement if you haven't already done. >>> Several components in carbon platform will be using the hazelcast based >>> clustering impl. We should have some mechanism to embed the usage of the >>> each cluster message into the message itself. >>> For eg. depsync messages will have the message type : depsync >>> cluster initialization/coordination messages will have >>> message type: cluster >>> etc. >>> (I'm aware there is some kind of identification via the cluster message >>> class, but I'm talking about embedding into api level.) >>> >>> So with this (message type), as the next step, we can have some rules on >>> which messages to re-play. >>> For eg: depsync messages, we can only re-play the latest (here we might >>> need to embed a timstamp into the message also). >>> WDYT? >>> >>> +1 >> We could have normal and reliable messaging APIs. >> >> +1 for cluster messages to have UUIDs for reliable messaging. >> >> IMHO the reliable messaging can also be implemented with the hazelcast >> cache, where we can store those messages in the cache and when a member >> joins/rejoins it can read the missed messages from the cache. but for this >> we have to use sequence numbers. >> >> This is just my thought, not sure how feasible it is. >> >> Suho >> >> thanks, >>> >>> >>> >>> >>> On Sat, Jul 6, 2013 at 2:30 PM, Afkham Azeez <az...@wso2.com> wrote: >>> >>>> I have implemented a simple replay mechanism based on message UUIDs. >>>> >>>> >>>> On Thu, Jul 4, 2013 at 5:44 PM, Afkham Azeez <az...@wso2.com> wrote: >>>> >>>>> There could be a situation where when a cluster message is sent, a >>>>> member momentarily leaves the cluster, but joins immediately. This >>>>> generally could happen when the nodes slow down under load, or due to >>>>> intermittent network failures. However, this could lead to failures >>>>> because >>>>> crucial cluster messages may not be received by members. >>>>> >>>>> To overcome this, or reduce the probability of loss of such messages, >>>>> we can replay a certain number of messages when a member joins. On the >>>>> sender side, messages over a particular time period can be buffered, and >>>>> then replayed when new members join. However, we should ensure that the >>>>> messages are idempotent, and messages should declare whether they are >>>>> idempotent or not. If a message is not idempotent, we will not replay it. >>>>> All the messages we have at the moment are idempotent, AFAIK. >>>>> >>>>> How does this approach sound? >>>>> >>>>> -- >>>>> *Afkham Azeez* >>>>> Director of Architecture; WSO2, Inc.; http://wso2.com >>>>> Member; Apache Software Foundation; http://www.apache.org/ >>>>> * <http://www.apache.org/>** >>>>> email: **az...@wso2.com* <az...@wso2.com>* cell: +94 77 3320919 >>>>> blog: **http://blog.afkham.org* <http://blog.afkham.org>* >>>>> twitter: >>>>> **http://twitter.com/afkham_azeez*<http://twitter.com/afkham_azeez> >>>>> * >>>>> linked-in: **http://lk.linkedin.com/in/afkhamazeez* >>>>> * >>>>> * >>>>> *Lean . Enterprise . Middleware* >>>>> >>>> >>>> >>>> >>>> -- >>>> *Afkham Azeez* >>>> Director of Architecture; WSO2, Inc.; http://wso2.com >>>> Member; Apache Software Foundation; http://www.apache.org/ >>>> * <http://www.apache.org/>** >>>> email: **az...@wso2.com* <az...@wso2.com>* cell: +94 77 3320919 >>>> blog: **http://blog.afkham.org* <http://blog.afkham.org>* >>>> twitter: >>>> **http://twitter.com/afkham_azeez*<http://twitter.com/afkham_azeez> >>>> * >>>> linked-in: **http://lk.linkedin.com/in/afkhamazeez* >>>> * >>>> * >>>> *Lean . Enterprise . Middleware* >>>> >>>> _______________________________________________ >>>> Architecture mailing list >>>> Architecture@wso2.org >>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>>> >>>> >>> >>> >>> -- >>> Supun Malinga, >>> >>> Senior Software Engineer, >>> WSO2 Inc. >>> http://wso2.com >>> http://wso2.org >>> email - sup...@wso2.com <sup...@wso2.com> >>> mobile - 071 56 91 321 >>> >>> _______________________________________________ >>> Architecture mailing list >>> Architecture@wso2.org >>> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >>> >>> >> >> >> -- >> *S. Suhothayan >> * >> Associate Technical Lead, >> *WSO2 Inc. *http://wso2.com * >> <http://wso2.com/>* >> lean . enterprise . middleware >> >> *cell: (+94) 779 756 757 | blog: http://suhothayan.blogspot.com/ >> twitter: http://twitter.com/suhothayan | linked-in: >> http://lk.linkedin.com/in/suhothayan* >> * >> * >> >> _______________________________________________ >> Architecture mailing list >> Architecture@wso2.org >> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >> >> > > > -- > ============================ > Srinath Perera, Ph.D. > http://people.apache.org/~hemapani/ > http://srinathsview.blogspot.com/ > > _______________________________________________ > Architecture mailing list > Architecture@wso2.org > https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture > > -- *Afkham Azeez* Director of Architecture; WSO2, Inc.; http://wso2.com Member; Apache Software Foundation; http://www.apache.org/ * <http://www.apache.org/>** email: **az...@wso2.com* <az...@wso2.com>* cell: +94 77 3320919 blog: **http://blog.afkham.org* <http://blog.afkham.org>* twitter: **http://twitter.com/afkham_azeez*<http://twitter.com/afkham_azeez> * linked-in: **http://lk.linkedin.com/in/afkhamazeez* * * *Lean . Enterprise . Middleware*
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