Re: [infinispan-dev] HotRod server and Rolling Upgrades

I don't like #1. Seems more complicated, harder to maintain & debug than the others. In my opinion the best option would be #4 (eliminate the different formats), but that probably can't be done in a minor release? Between 2 and 3, I'd prefer #2, handling it in the base class so it's automatically inherited by any custom classes that extend it. Since the use case isn't limited to rolling upgrades; you could have a HotRod cache with a full-time RemoteCacheStore. -Dennis On 12/11/2012 07:02 AM, Tristan Tarrant wrote: > > So, > I thought we had everything ready to go for HotRod rolling upgrades: > > have HotRod server full of data (the "source") > configure a new HotRod server (the "target") with a RemoteCacheStore pointing to the "source" (using "rawValues") > clients switch over to the "target" server which on cache misses should seamlessly fetch entries from the "source" > issue a "dump keys" on the source > fetch the "dumped keys" from the target > disable the RCS on the target and switch off the "source" for good > PROFIT$$$ > Unfortunately there is a teeny tiny flaw in the plan: entries in a HotRod-managed cache are ByteArrayKey/CacheValue pairs and unfortunately, when the "target" reads from the RCS they get unwrapped into their byte[] equivalents. > The solutions we have are: > have a special marshaller placed on the RemoteCacheStore's RemoteCacheManager which rewraps the entries. Unfortunately marshallers can't distinguish between keys and values, so this would probably require some horrid ThreadLocal trickery > Add a new option to RemoteCacheStore so that it rewraps entries in the ByteArrayKey/CacheValue format. Unfortunately the CacheValue class is part of server-core, but the dependency could be made optional, and in the context of the Rolling Upgrade scenario it is a non-issue, since it will be in the classpath > Introduce a new MigrationRemoteCacheStore which does the same as the above, but without changing RCS itself. > My personal favourite is number 2, but I trust your better judgement. > I think these are merely workarounds and we should have a better way for "entry wrappers" (such as the cache servers) to "localize" the entries for their own particular needs. Also I believe we need a better way to attach metadata to entries in a portable way so that we don't need these value wrappers. > Tristan > > _______________________________________________ > infinispan-dev mailing list > infinispan-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/infinispan-dev _______________________________________________ infinispan-dev mailing list infinispan-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/infinispan-dev