(Sorry not to reply to Ning Li's message, but I just subscribed to the list, and don't know how to reply to it without it being in my inbox.)
This is just my quick naïve stab at how resynching might work: - When the master is notified of a slave, it makes a persistent note of the slave's identity (presumably URI). - When the master goes down, the slave begins operating as it does now. It also starts a new transacted message queue (the "resynch queue") for all the messages and acknowledgements it's going to process while it is in the hot seat. - When the master comes back up: o Before it begins responding to messages, it looks for its persistent note, and finds the slave. o It connects to the slave and tells it that their places are reversed. The Servant Has Become The Master. Biblical scholars and Police fans laugh. (FROM NOW ON, I'LL REFER TO THE BROKERS USING THEIR NEW ROLES.) The new slave will not process messages from anybody but the new master. o The new slave begins consuming resynch messages from the queue, as well as those new messages that come from its new master via the good ole' master-slave protocol, processing each in the same way. Er, somehow. If I correctly understand how clients work, then the next step should not require any notification to the clients: - The slave and master agree to swap places. The swap takes place atomically with respect to all of the ongoing synchronization processing between them. (NOW I'LL REFER TO THE BROKERS IN THE ROLES THEY HAD BEFORE FAILOVER.) At this point the slave stops processing requests, and the master starts; clients should be able to failover just as they do now. If someone wants to point me the way to relevant code, I'll check it out. Perhaps I've really oversimplified things...if so, please tell me where. Larry Edelstein Revere Data San Francisco, CA --- on Mon March 6, Ning Li wrote: --- Maybe a broker-broker synchronization protocol is the ultimate solution, just we are not sure how to get there. Any recommendation or suggestions? - ABOUT REVERE - Revere provides finance and business professionals with superior data and analytics on companies traded publicly in the U.S. Our approach is based on precise classification and identification of key business relationships. The Revere Complete product suite combines the Revere Research analysis platform and the Revere RealTime market data application. Revere Complete integrates comprehensive financial and market information - real-time quotes, sector and option analytics, charts, news, fundamental data, and sophisticated screening - with unique content derived from Revere's own independent research: - The Revere Hierarchy, a patented classification system that provides unmatched detail in specifying a company's business activities and identifying exact competitors - Revere Relationships, a database mapping a company to its key competitors, customers, suppliers, and strategic partners www.reveredata.com
