Am 20.10.15 um 21:06 schrieb Oliver Lietz: > On Monday 19 October 2015 14:46:05 Carsten Ziegeler wrote: >> Hi, > > hi, > >> with https://issues.apache.org/jira/browse/SLING-4751 we have a new API >> for dealing with change events on both sides, the reporting part and the >> client using the events. The basic idea is to have a more scalable approach. >> >> Now, if we think of large scalable systems, there is one thing that is >> not very optimal: dealing with external observation events. Obviously >> sending all observation events to all potentially interested parties is >> not really cheap. >> There are additional things, like e.g. Oak is not providing the commit >> info for external events. Therefore the user of the change is unknown. >> With other resource providers, like mongo, cassandra etc. there is not >> even an infrastructure to send external change events across instances. >> >> I was wondering what is the best way to deal with this. It would be >> great if we could just say: observation is only for local changes. This >> would simplify a lot of things and makes scaling observation handling >> much easier. >> For a lot of things, this is usually sufficient. For example, if you >> want to trigger an action based on some changes, you want to trigger >> this action only once anyway. Doing it on the instance where the change >> happened is therefore straightforward. >> Unfortunately, there are use cases where you want to receive external >> changes, and these usually boil down to caching use caches. For example >> the jsp script cache needs to be aware of jsp changes, no matter where >> the change happened. >> All these use cases could be changed to different patterns, e.g. on >> access check if the cached entry is still valid, period checks etc. On >> the other hand, an on access cache reduces general request performance >> dramatically, period checks have the downside that there is a delay of >> detecting the change etc. An observation based cache is pretty optimal >> as it only invalidates if there is a change and it only checks/recreates >> a cached entry if necessary. >> >> With the move to the new observation api we now have the chance to come >> up with the best solution. We just need to figure out, what this is. >> >> Thoughts? > > have you considered something like Apache Ignite or Apache Kafka? >
Can you elaborate on how this could help? Regards Carsten > Regards, > O. > >> Regards >> Carsten > > -- Carsten Ziegeler Adobe Research Switzerland [email protected]
