onPartitionAssigned called also at startup - for the first partitions a consumer gets?

2018-03-26 Thread Marasoiu, Nicu
Hi, The "rebalancing" callback is also called for the partitions the consumer gets when it starts up and joins the consumer group? Thank you, Nicu Marrasoiu Geschäftsanschrift/Business address: METRO SYSTEMS GmbH, Metro-Straße 12, 40235 Düsseldorf, Germany Aufsichtsrat/Supervisory Board: Heiko Hu

poll(0)

2018-03-22 Thread Marasoiu, Nicu
Hi, Is it correct that out of all the consumer api calls, only poll does any real activity? Is it safe to assume that poll(0) will only fetch metadata, but will not have time to get any response on select, returning an empty list of consumerRecords? Excepting of course the case of thread being s

transactional behavior offsets+effects

2018-03-12 Thread Marasoiu, Nicu
Hi, We would consider one of 2 or 3 flows to ensure an "exactly once" process from an input kafka topic to a database storing results (using kafka consumer, but also evaluated kafka streams and details at the end) and wanted to gather your input on them: (for simplicity let's assume that any exc

RE: transactional behavior offsets+effects

2018-03-12 Thread Marasoiu, Nicu
p, iterate through partitions and resume one partition, do poll, process, then next partition, in rotation? Thank you, Nicu Marasoiu ____ From: Marasoiu, Nicu Sent: Monday, March 12, 2018 8:58 AM To: users@kafka.apache.org Subject: transactional behavior offsets+effec

exactly once and storing offsets in db (transactionally with computation results)

2018-03-12 Thread Marasoiu, Nicu
Hi, We would consider one of 2 or 3 flows to ensure an "exactly once" process from an input kafka topic to a database storing results (using kafka consumer, but also evaluated kafka streams and details at the end) and wanted to gather your input on them: (for simplicity let's assume that any ex

aggregation tables mirrored in kafka & rocksdb

2018-02-28 Thread Marasoiu, Nicu
Hi, Currently we have an aggregation system (without kafka) where events are aggregated into Cassandra tables holding aggregate results. We are considering moving to a KafkaStreams solution with exactly-once processing but in this case it seems that all the aggregation tables (reaching TB) need

kafka streams, docker/k18s and rocksdb - storage performance

2018-02-28 Thread Marasoiu, Nicu
Hi, When using kafka streams & stateful transformations (rocksdb) and docker and Kubernetes, what are the concerns for storage - I mean, I know that writing to disk in Docker into the container is less performant than mounting a direct volume. However, in our setup a separate team is handling, a

RE: question on doing deduplication with KafkaStreams

2018-02-27 Thread Marasoiu, Nicu
))) .reduce((val1, val2) -> val1) From: Marasoiu, Nicu [nicu.maras...@metrosystems.net] Sent: Tuesday, February 27, 2018 11:03 AM To: users@kafka.apache.org Subject: question on doing deduplication with KafkaStreams Hi, >From a progr

question on doing deduplication with KafkaStreams

2018-02-27 Thread Marasoiu, Nicu
Hi, >From a programatic perspective, doing a groupByKey.reduce((val1, val2) -> >val1) would deduplicate entries, but then I have a few questions: this state >would accumulate without limit, right? Should we do a windowing, to eliminate >old records be needed, right? Will the state accumulate jus

RE: commiting consumed offsets synchronously (every message)

2018-02-21 Thread Marasoiu, Nicu
hem? It's tough to be more specific without knowing more specifics, but maybe that helps a bit already? Best regards, Sönke On Wed, Feb 21, 2018 at 11:57 AM, Marasoiu, Nicu < nicu.maras...@metrosystems.net> wrote: > Hi, > In order to obtain an exactly-once semantics, we are thin

commiting consumed offsets synchronously (every message)

2018-02-21 Thread Marasoiu, Nicu
Hi, In order to obtain an exactly-once semantics, we are thinking of doing at-least-once processing, and then have a compensation mechanism to fix the results in few minutes by correcting them by substracting the effects of the duplicates. However, in order to do that, it seems that at least thi