Can a Kafka consumer read from multiple topics?

Apache Kafka allows a single consumer to subscribe to multiple topics at the same time and process both in a combined stream of records.

How do you consume multiple topics in Kafka?

In order to consume messages from kafka topic, you need to create a kafka consumer, and subscribe it into the topic. Every kafka consumer is grouped by consumer group name. It allows you to consume the whole topic using multiple physical instances of the application, and process distinct messages on each instance.

Can multiple producers write to same Kafka topic?

Kafka is able to seamlessly handle multiple producers that are using many topics or the same topic. The consumer subscribes to one or more topics and reads the messages.

What is KTable in Kafka?

KTable is an abstraction of a changelog stream from a primary-keyed table. Each record in this changelog stream is an update on the primary-keyed table with the record key as the primary key.

What is KStream in Kafka?

KStream is an abstraction of a record stream of KeyValue pairs, i.e., each record is an independent entity/event in the real world. For example a user X might buy two items I1 and I2, and thus there might be two records , in the stream.

Can a Kafka consumer read from multiple partitions?

A consumer can be assigned to consume multiple partitions. So the rule in Kafka is only one consumer in a consumer group can be assigned to consume messages from a partition in a topic and hence multiple Kafka consumers from a consumer group can not read the same message from a partition.

Can a consumer read from multiple topics?

A consumer must subscribe to topics to retrieve the records stored in them. To be clear, a single consumer can subscribe to multiple topics at once. You do not have to make a separate consumer per topic.

What is multithreading in Kafka?

Multithreading is “the ability of a central processing unit (CPU) (or a single core in a multi-core processor) to provide multiple threads of execution concurrently, supported by the operating system.” In situations where the work can be divided into smaller units, which can be run in parallel, without negative effects …

Can a topic be written by multiple producers?

Short answer to this one is Yes, the individual producer’s events will be guaranteed to be in order. Messages in Kafka are appended to a topic partition in the order they are sent and the consumers read the messages in the same order they are stored in the topic partition.

Can two consumers read from same partition in Kafka?

While Kafka allows only one consumer per topic partition, there may be multiple consumer groups reading from the same partition. Multiple consumers may subscribe to a Topic under a common Consumer Group ID, although in this case, Kafka switches from sub/pub mode to a queue messaging approach.

Can multiple consumers read from the same topic in Kafka?

Just like multiple producers can write to the same topic, we need to allow multiple consumers to read from the same topic, splitting the data between them. Kafka consumers are typically part of a consumer group.

What is the use of Kafka Streams?

It is useful when you are facing, both a source and a target system of your data being Kafka. At first sight, you might spot that the definition of processing in Kafka Streams is surprisingly similar to Stream API from Java. You just use fluent API to specify all the maps and joins.

What is the maximum amount of memory a Kafka consumer needs?

The default is 1 MB, which means that when KafkaConsumer.poll () returns ConsumerRecords, the record object will use at most max.partition.fetch.bytes per partition assigned to the consumer. So if a topic has 20 partitions, and you have 5 consumers, each consumer will need to have 4 MB of memory available for ConsumerRecords.

What is difference between queue and topic in Kafka?

Kafka topicsare not queues, because once a message is consumed from a topic, it stays there(unless its lifetime has expired) and the offsetmoves to the next, whereas for a queue, once a message is consumed, the message is removed from that queue. Ordered sets is also by partitionsonly.