absurdfarce commented on PR #2034: URL: https://github.com/apache/cassandra-java-driver/pull/2034#issuecomment-2837428237
I don't claim any familiarity with the current work on CRaC but I have some concerns here that aren't different from what @lukasz-antoniak and @aratno are talking about above. The question with in-flight requests isn't simply whether the driver will retry them; we use counts of in-flight requests as a proxy for the load on a node in the default load balancing policy. The disconnect between the (potentially very stale) data represented by in-flight requests and snapshot time vs. the current state of a system could very easily lead to some strange LBP operations. You'd almost be better off somehow capturing the driver state after establishing a control connection but before any individual connections are established... but that brings you into the areas @aratno was referring to (or at least I think he was). The driver gathers a fair amount of metadata information when it establishes a control connection to the cluster; if we include this data in any kind of snapshot state it would have to be revalidated when we (re)connect anyway. But if we're already doing such a revalidation is there... a benefit to pre-loading it in the first place? So much of what the control connection does is built up from information it gets from the server.. it just seems hard to imagine how much of it could be safely cached in a way that would give you clear performance wins. I also haven't spent any time looking at what Project Leyden is doing but it does seem like AOT classloading might be a reasonable way to get some level of performance gain without delving too far into the handling of information we get from the cluster. I'm very interested to hear how these approaches compare in your thinking @rvansa. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For additional commands, e-mail: pr-h...@cassandra.apache.org
