Thanks for the clarifications, that all makes sense. I'm ready to vote on the KIP, but can you just update the KIP first to address Bruno's feedback? Ie just fix the tags and fill in the missing fields.
For example it sounds like these would be thread-level metrics. You should be able to figure out what the values should be from the KIP-444 doc, there's a chart with the type and tags for all thread-level metrics. Not 100% sure what Bruno meant by "group" but my guess would be whether it's INFO/DEBUG/TRACE. This is probably one of the most important things to include in a KIP that's introducing new metrics: how big is the potential performance impact of recording these metrics? How big is the intended audience, would these be useful to almost everyone or are they more "niche"? It sounds like maybe DEBUG would be most appropriate here -- WDYT? -Sophie On Thu, Jul 22, 2021 at 9:01 AM Bruno Cadonna <cado...@apache.org> wrote: > Hi Rohan, > > Thank you for the KIP! > > I agree that the KIP is well-motivated. > > What is not very clear is the metadata like type, group, and tags of the > metrics. For example, there is not application-id tag in Streams and > there is also no producer-id tag. The clients, i.e., producer, admin, > consumer, and also Streams have a client-id tag, that corresponds to the > producer-id, consumer-id, etc you use in the KIP. > > For examples of metadata used in Streams you can look at the following > KIPs: > > - > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-444%3A+Augment+metrics+for+Kafka+Streams > - > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-471%3A+Expose+RocksDB+Metrics+in+Kafka+Streams > - > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-607%3A+Add+Metrics+to+Kafka+Streams+to+Report+Properties+of+RocksDB > - > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-613%3A+Add+end-to-end+latency+metrics+to+Streams > > > Best, > Bruno > > On 22.07.21 09:42, Rohan Desai wrote: > > re sophie: > > > > The intent here was to include all blocked time (not just `RUNNING`). The > > caller can window the total blocked time themselves, and that can be > > compared with a timeseries of the state to understand the ratio in > > different states. I'll update the KIP to include `committed`. The admin > API > > calls should be accounted for by the admin client iotime/iowaittime > > metrics. > > > > On Tue, Jul 20, 2021 at 11:49 PM Rohan Desai <desai.p.ro...@gmail.com> > > wrote: > > > >>> I remember now that we moved the round-trip PID's txn completion logic > >> into > >> init-transaction and commit/abort-transaction. So I think we'd count > time > >> as in StreamsProducer#initTransaction as well (admittedly it is in most > >> cases a one-time thing). > >> > >> Makes sense - I'll update the KIP > >> > >> On Tue, Jul 20, 2021 at 11:48 PM Rohan Desai <desai.p.ro...@gmail.com> > >> wrote: > >> > >>> > >>>> I had a question - it seems like from the descriptionsof > >>> `txn-commit-time-total` and `offset-commit-time-total` that they > measure > >>> similar processes for ALOS and EOS, but only `txn-commit-time-total` is > >>> included in `blocked-time-total`. Why isn't `offset-commit-time-total` > also > >>> included? > >>> > >>> I've updated the KIP to include it. > >>> > >>>> Aside from `flush-time-total`, `txn-commit-time-total` and > >>> `offset-commit-time-total`, which will be producer/consumer client > >>> metrics, > >>> the rest of the metrics will be streams metrics that will be thread > level, > >>> is that right? > >>> > >>> Based on the feedback from Guozhang, I've updated the KIP to reflect > that > >>> the lower-level metrics are all client metrics that are then summed to > >>> compute the blocked time metric, which is a Streams metric. > >>> > >>> On Tue, Jul 20, 2021 at 11:58 AM Rohan Desai <desai.p.ro...@gmail.com> > >>> wrote: > >>> > >>>>> Similarly, I think "txn-commit-time-total" and > >>>> "offset-commit-time-total" may better be inside producer and consumer > >>>> clients respectively. > >>>> > >>>> I agree for offset-commit-time-total. For txn-commit-time-total I'm > >>>> proposing we measure `StreamsProducer.commitTransaction`, which wraps > >>>> multiple producer calls (sendOffsets, commitTransaction) > >>>> > >>>>>> For "txn-commit-time-total" specifically, besides > >>>> producer.commitTxn. > >>>> other txn-related calls may also be blocking, including > >>>> producer.beginTxn/abortTxn, I saw you mentioned "txn-begin-time-total" > >>>> later in the doc, but did not include it as a separate metric, and > >>>> similarly, should we have a `txn-abort-time-total` as well? If yes, > >>>> could > >>>> you update the KIP page accordingly. > >>>> > >>>> `beginTransaction` is not blocking - I meant to remove that from that > >>>> doc. I'll add something for abort. > >>>> > >>>> On Mon, Jul 19, 2021 at 11:55 PM Rohan Desai <desai.p.ro...@gmail.com > > > >>>> wrote: > >>>> > >>>>> Thanks for the review Guozhang! responding to your feedback inline: > >>>>> > >>>>>> 1) I agree that the current ratio metrics is just "snapshot in > >>>>> point", and > >>>>> more flexible metrics that would allow reporters to calculate based > on > >>>>> window intervals are better. However, the current mechanism of the > >>>>> proposed > >>>>> metrics assumes the thread->clients mapping as of today, where each > >>>>> thread > >>>>> would own exclusively one main consumer, restore consumer, producer > and > >>>>> an > >>>>> admin client. But this mapping may be subject to change in the > future. > >>>>> Have > >>>>> you thought about how this metric can be extended when, e.g. the > >>>>> embedded > >>>>> clients and stream threads are de-coupled? > >>>>> > >>>>> Of course this depends on how exactly we refactor the runtime - > >>>>> assuming that we plan to factor out consumers into an "I/O" layer > that is > >>>>> responsible for receiving records and enqueuing them to be processed > by > >>>>> processing threads, then I think it should be reasonable to count > the time > >>>>> we spend blocked on this internal queue(s) as blocked. The main > concern > >>>>> there to me is that the I/O layer would be doing something expensive > like > >>>>> decompression that shouldn't be counted as "blocked". But if that > really is > >>>>> so expensive that it starts to throw off our ratios then it's > probably > >>>>> indicative of a larger problem that the "i/o layer" is a bottleneck > and it > >>>>> would be worth refactoring so that decompression (or insert other > expensive > >>>>> thing here) can also be done on the processing threads. > >>>>> > >>>>>> 2) [This and all below are minor comments] The "flush-time-total" > may > >>>>> better be a producer client metric, as "flush-wait-time-total", than > a > >>>>> streams metric, though the streams-level "total-blocked" can still > >>>>> leverage > >>>>> it. Similarly, I think "txn-commit-time-total" and > >>>>> "offset-commit-time-total" may better be inside producer and consumer > >>>>> clients respectively. > >>>>> > >>>>> Good call - I'll update the KIP > >>>>> > >>>>>> 3) The doc was not very clear on how "thread-start-time" would be > >>>>> needed > >>>>> when calculating streams utilization along with total-blocked time, > >>>>> could > >>>>> you elaborate a bit more in the KIP? > >>>>> > >>>>> Yes, will do. > >>>>> > >>>>>> For "txn-commit-time-total" specifically, besides > producer.commitTxn. > >>>>> other txn-related calls may also be blocking, including > >>>>> producer.beginTxn/abortTxn, I saw you mentioned > "txn-begin-time-total" > >>>>> later in the doc, but did not include it as a separate metric, and > >>>>> similarly, should we have a `txn-abort-time-total` as well? If yes, > >>>>> could > >>>>> you update the KIP page accordingly. > >>>>> > >>>>> Ack. > >>>>> > >>>>> On Mon, Jul 12, 2021 at 11:29 PM Rohan Desai < > desai.p.ro...@gmail.com> > >>>>> wrote: > >>>>> > >>>>>> Hello All, > >>>>>> > >>>>>> I'd like to start a discussion on the KIP linked above which > proposes > >>>>>> some metrics that we would find useful to help measure whether a > Kafka > >>>>>> Streams application is saturated. The motivation section in the KIP > goes > >>>>>> into some more detail on why we think this is a useful addition to > the > >>>>>> metrics already implemented. Thanks in advance for your feedback! > >>>>>> > >>>>>> Best Regards, > >>>>>> > >>>>>> Rohan > >>>>>> > >>>>>> On Mon, Jul 12, 2021 at 12:00 PM Rohan Desai < > desai.p.ro...@gmail.com> > >>>>>> wrote: > >>>>>> > >>>>>>> > >>>>>>> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-761%3A+Add+Total+Blocked+Time+Metric+to+Streams > >>>>>>> > >>>>>> > > >
