Regarding the stress tests, if you’re willing to share, I’m starting a repo where we can keep a bunch of different stress profiles. I’d like to start running them on releases before we agree to push them out. If anyone has a stress test they are willing to share, please get in touch with me!
> On Oct 16, 2017, at 8:37 AM, Jeff Jirsa <jji...@gmail.com> wrote: > > I got some feedback last week that I should try this on Monday morning, so > let's see if we can nudge a few people into action this week. > > 3.0.15 and 3.11.1 are released. This is a dev list, so that shouldn't be a > surprise to anyone here - you should have seen the votes and release > notifications. The people working directly ON Cassandra every day are > probably very aware of the number and nature of fixes in those versions - > if you're not aware, the Change lists are HUGE, and some of the fixes are > VERY IMPORTANT. So this week's wrap-up is really a reflection on the size > of those two release changelogs. > > One of the advantages of the Cassandra project is the size of the user base > - I don't know if we have accurate counts (and some of the "surveys" are > laughable), but we know it's on the order of thousands (probably tens of > thousands) of companies, and some huge number of instances (not willing to > speculate here, we know it's at least in the hundreds of thousands, may be > well into the millions). Historically, the best stabilizer of a release was > people upgrading their unusual use cases, finding bugs that the developers > hadn't anticipated (and therefore tests didn't exist for those edge cases), > reporting them, and the next release would be slightly better than the one > before it. The chicken/egg problem here is pretty obvious, and while a lot > of us are spending a lot of time making things better, I want to use this > email to ask a favor (in 3 parts): > > 1) If you haven't tried 3.0 or 3.11 yet, please spin it up on a test > cluster. 3.11 would be better, 3.0 is ok too. It doesn't need to be a > thousand node cluster, most of the weird stuff we've seen in the post-3.0 > world deals with data, not cluster size. Grab some of your prod data if you > can, throw it into a test cluster, add a node/remove a node, tell us if it > doesn't work. > 2) Please run a stress workload against that test cluster, even if it's > 5-10 minutes. Purpose here is two-fold: like #1, it'll help us find some > edge cases we haven't seen before, but it'll also help us identify holes in > stress coverage. We have some tickets to add UDTs to stress ( > https://issues.apache.org/jira/browse/CASSANDRA-13260 ) and LWT ( > https://issues.apache.org/jira/browse/CASSANDRA-7960 ). Ideally your stress > profile should be more than "80% reads 20% writes" - try to actually model > your schema and query behavior. Do you use static columns? Do you use > collections? If you're unable to model your use case because of a > deficiency in stress, open a JIRA. If things break, open a JIRA. If it > works perfectly, I'm interested in seeing your stress yaml and results > (please send it to me privately, don't spam the list). > 3) If you're somehow not able to run stress because you don't have hardware > for a spare cluster, profiling your live cluster is also incredibly useful. > TLP has some notes on how to generate flame graphs - > https://github.com/thelastpickle/lightweight-java-profiler - I saw one > example from a cluster that really surprised me. There are versions and use > cases that we know have been heavily profiled, but there are probably > versions and use cases where nobody's ever run much in the way of > profiling. If you're running openjdk in prod, and you're able to SAFELY > attach a profiler to generate some flame graphs, please send those to me > (again, privately please, I don't think the whole list needs a copy). > > My hope in all of this is to build up a corpus of real world use cases (and > real current state via profiling) that we can leverage to make testing and > performance better going forward. If I get much in the way of response to > either of these, I'll try to send out a summary in next week's email). > > - Jeff --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org For additional commands, e-mail: dev-h...@cassandra.apache.org
