http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Kafka-connector-issue-tp22367p22374.html
It looks like it is some issue with backpressure as the same behavior happens with the client library as a custom source.
> On Aug 16, 2018, at 6:59 PM, TechnoMage <
[hidden email]> wrote:
>
> I have seen this in the past and running into it again.
>
> I have a kafka consumer that is not getting all the records from the topic. Kafka conforms there are 300k messages in each partition, and flink only sees a total of 8000 records in the source.
>
> Kafka is 2.0, flink is 1.4.2 connector is FlinkKafkaConsumer011
>
> Properties props = new Properties();
> props.setProperty("bootstrap.servers", servers);
> props.setProperty("group.id", UUID.randomUUID().toString());
> props.setProperty("flink.partition-discovery.interval-millis", "10000");
> props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
> DataStream<String> ds = consumers.get(a.eventType);
> if (ds == null) {
> FlinkKafkaConsumer011<String> cons = new FlinkKafkaConsumer011<String>(
> topic, new SimpleStringSchema(), props);
> cons.setStartFromEarliest();
> ds = env.addSource(cons).name(et.name).rebalance();
> consumers.put(a.eventType, ds);
> }
>
> I am about to rip out the kafka consumer and build a source using the client library which has been 100% reliable in working with kafka. Any pointers welcome.
>
> Michael
>