Do you know why your consumers are so slow? 12E6msg/hour is 3333msg/s, which is not very high from a Kafka point-of-view. As you're doing database inserts, I suspect that is where the bottleneck lies.
If, for example, you're doing a single-row insert in a SQL DB for every message then this would incur a lot of overhead. Yes, you can somewhat alleviate that by parallellising - i.e. increasing the partition count - but it is also worth looking at batch inserts, if you aren't yet. Say, each consumer waits for 1000 messages or 5 seconds to have passed (whichever comes first) and then does a single bulk insert of the msgs it has received, followed by a manual commit. [A] you might already be doing this and [B] your DB of choice might not support bulk inserts (although most do), but otherwise I'd expect this to work a lot better than increasing the partition count. On Mon, Dec 21, 2020 at 8:10 AM Haruki Okada <ocadar...@gmail.com> wrote: > About load test: > I think it'd be better to monitor per-message process latency and estimate > required partition count based on it because it determines the max > throughput per single partition. > - Say you have to process 12 million messages/hour = 3333 messages/sec . > - If you have 7 partitions (thus 7 parallel consumers at maximum), single > consumer should process 3333 / 7 = 476 messages/sec > - It means, process latency per single message should be lower than 2.1 > milliseconds (1000 / 476) > => If you have 14 partitions, it becomes 4.2 milliseconds > > So required partition count can be calculated by per-message process > latency. (I think Spring-Kafka can be easily integrated with prometheus so > you can use it to measure that) > > About increasing instance count: > - It depends on current system resource usage. > * If the system resource is not so busy (likely because the consumer just > almost waits DB-write to return), you don't need to increase consumer > instances > * But I think you should make sure that single consumer instance isn't > assigned multiple partitions to fully parallelize consumption across > partitions. (If I remember correctly, ConcurrentMessageListenerContainer > has a property to configure the concurrency) > > 2020年12月21日(月) 15:51 Yana K <yanak1...@gmail.com>: > > > So as the next step I see to increase the partition of the 2nd topic - > do I > > increase the instances of the consumer from that or keep it at 7? > > Anything else (besides researching those libs)? > > > > Are there any good tools for load testing kafka? > > > > On Sun, Dec 20, 2020 at 7:23 PM Haruki Okada <ocadar...@gmail.com> > wrote: > > > > > It depends on how you manually commit offsets. > > > Auto-commit does commits offsets in async manner basically, so as long > as > > > you do manual-commit in the same way, there should be no much > > difference. > > > > > > And, generally offset-commit mode doesn't make much difference in > > > performance regardless manual/auto or async/sync unless offset-commit > > > latency takes significant amount in processing time (e.g. you commit > > > offsets synchronously in every poll() loop). > > > > > > 2020年12月21日(月) 11:08 Yana K <yanak1...@gmail.com>: > > > > > > > Thank you so much Marina and Haruka. > > > > > > > > Marina's response: > > > > - When you say " if you are sure there is no room for perf > optimization > > > of > > > > the processing itself :" - do you mean code level optimizations? Can > > you > > > > please explain? > > > > - On the second topic you say " I'd say at least 40" - is this based > on > > > 12 > > > > million records / hour? > > > > - "if you can change the incoming topic" - I don't think it is > > possible > > > :( > > > > - "you could artificially achieve the same by adding one more step > > > > (service) in your pipeline" - this is the next thing - but I want to > be > > > > sure this will help, given we've to maintain one more layer > > > > > > > > Haruka's response: > > > > - "One possible solution is creating an intermediate topic" - I > already > > > did > > > > it > > > > - I'll look at Decaton - thx > > > > > > > > Is there any thoughts on the auto commit vs manual commit - if it can > > > > better the performance while consuming? > > > > > > > > Yana > > > > > > > > > > > > > > > > On Sat, Dec 19, 2020 at 7:01 PM Haruki Okada <ocadar...@gmail.com> > > > wrote: > > > > > > > > > Hi. > > > > > > > > > > Yeah, Spring-Kafka does processing messages sequentially, so the > > > consumer > > > > > throughput would be capped by database latency per single process. > > > > > One possible solution is creating an intermediate topic (or > altering > > > > source > > > > > topic) with much more partitions as Marina suggested. > > > > > > > > > > I'd like to suggest another solution, that is multi-threaded > > processing > > > > per > > > > > single partition. > > > > > Decaton (https://github.com/line/decaton) is a library to achieve > > it. > > > > > > > > > > Also confluent has published a blog post about parallel-consumer ( > > > > > > > > > > > > > > > > > > > > https://www.confluent.io/blog/introducing-confluent-parallel-message-processing-client/ > > > > > ) > > > > > for that purpose, but it seems it's still in the BETA stage. > > > > > > > > > > 2020年12月20日(日) 11:41 Marina Popova <ppine7...@protonmail.com > > .invalid>: > > > > > > > > > > > The way I see it - you can only do a few things - if you are sure > > > there > > > > > is > > > > > > no room for perf optimization of the processing itself : > > > > > > 1. speed up your processing per consumer thread: which you > already > > > > tried > > > > > > by splitting your logic into a 2-step pipeline instead of 1-step, > > and > > > > > > delegating the work of writing to a DB to the second step ( make > > sure > > > > > your > > > > > > second intermediate Kafka topic is created with much more > > partitions > > > to > > > > > be > > > > > > able to parallelize your work much higher - I'd say at least 40) > > > > > > 2. if you can change the incoming topic - I would create it with > > many > > > > > more > > > > > > partitions as well - say at least 40 or so - to parallelize your > > > first > > > > > step > > > > > > service processing more > > > > > > 3. and if you can't increase partitions for the original topic ) > - > > > you > > > > > > could artificially achieve the same by adding one more step > > (service) > > > > in > > > > > > your pipeline that would just read data from the original > > 7-partition > > > > > > topic1 and just push it unchanged into a new topic2 with , say 40 > > > > > > partitions - and then have your other services pick up from this > > > topic2 > > > > > > > > > > > > > > > > > > good luck, > > > > > > Marina > > > > > > > > > > > > Sent with ProtonMail Secure Email. > > > > > > > > > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > > > > > On Saturday, December 19, 2020 6:46 PM, Yana K < > > yanak1...@gmail.com> > > > > > > wrote: > > > > > > > > > > > > > Hi > > > > > > > > > > > > > > I am new to the Kafka world and running into this scale > problem. > > I > > > > > > thought > > > > > > > of reaching out to the community if someone can help. > > > > > > > So the problem is I am trying to consume from a Kafka topic > that > > > can > > > > > > have a > > > > > > > peak of 12 million messages/hour. That topic is not under my > > > control > > > > - > > > > > it > > > > > > > has 7 partitions and sending json payload. > > > > > > > I have written a consumer (I've used Java and Spring-Kafka lib) > > > that > > > > > will > > > > > > > read that data, filter it and then load it into a database. I > ran > > > > into > > > > > a > > > > > > > huge consumer lag that would take 10-12hours to catch up. I > have > > 7 > > > > > > > instances of my application running to match the 7 partitions > > and I > > > > am > > > > > > > using auto commit. Then I thought of splitting the write logic > > to a > > > > > > > separate layer. So now my architecture has a component that > reads > > > and > > > > > > > filters and produces the data to an internal topic (I've done 7 > > > > > > partitions > > > > > > > but as you see it's under my control). Then a consumer picks up > > > data > > > > > from > > > > > > > that topic and writes it to the database. It's better but still > > it > > > > > takes > > > > > > > 3-5hours for the consumer lag to catch up. > > > > > > > Am I missing something fundamentally? Are there any other ideas > > for > > > > > > > optimization that can help overcome this scale challenge. Any > > > pointer > > > > > and > > > > > > > article will help too. > > > > > > > > > > > > > > Appreciate your help with this. > > > > > > > > > > > > > > Thanks > > > > > > > Yana > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > ======================== > > > > > Okada Haruki > > > > > ocadar...@gmail.com > > > > > ======================== > > > > > > > > > > > > > > > > > > -- > > > ======================== > > > Okada Haruki > > > ocadar...@gmail.com > > > ======================== > > > > > > > > -- > ======================== > Okada Haruki > ocadar...@gmail.com > ======================== >
