I added some comments to the proposal. There a few concerns, but I like the idea in general.
Dan said: I remember someone trying to accomplish this same thing on top of geode with TransactionListener that dumped into a separate region or something like that. I think both Charlie and I have implemented this idea a few times, Here is the basic idea: The data region defines a TransactionListener with an afterCommit that: - creates a UnitOfWork object - creates an Event for each CacheEvent in the TransactionEvent event that contains: - regionName - operation - key - value - potentially other things like EventID, VersionTag, TXId - puts the UnitOfWork into a transaction region that has a gateway sender attached to it. It also has a CacheWriter attached to it. On the remote site, the CacheWriter attached to the transaction region: - begins a transaction - iterates the UnitOfWork's Events and executes each one - commits the transaction There are definitely some caveats to this: - There is a race condition between the commit in the data region and the TransactionListener afterCommit invocation doing the put into the transaction region. If the server crashes after the put into the data region but before the afterCommit callback, there will be data loss. In that case, the transaction in question will not have been stored in the transaction region and not be sent to the remote site. - Ideally, the data and transaction regions should be colocated, but that is a tricky. - What happens if a transaction fails in the remote site? - The transaction region has to be cleared periodically. - Knowing when to process the transaction in the CacheWriter is a bit tricky. It only needs to happen for transactions that originated remotely. Adding distributed system id to the UnitOfWork is one way to address this. Thanks, Barry Oglesby On Thu, Mar 26, 2020 at 7:34 AM Jacob Barrett <jbarr...@pivotal.io> wrote: > Great idea. I called out some similar areas of concerns and spit balled > some solutions to get the conversations flowing. > > -Jake > > > > On Mar 25, 2020, at 8:04 AM, Alberto Gomez <alberto.go...@est.tech> > wrote: > > > > Hi, > > > > Could you please review the RFC for "Gateway sender to deliver > transaction events atomically to receivers"? > > > > > https://cwiki.apache.org/confluence/display/GEODE/Gw+sender+to+deliver+transaction+events+atomically+to+receivers > > > > Deadline for comments is Wednesday, April 1st, 2020, > > > > Thanks, > > > > Alberto G. > >
