kafka partition strategy

Fortunately, Kafka allows users to select a partitioning strategy by configuring a Partitioner class. The Partitioner assigns the partition for each record. The default behavior is to hash the key of a record to get the partition, but some records may have a key that is null .

1. How many partitions should a Kafka topic have?
2. How does Kafka producer decide partition?
3. How are partitions assigned in Kafka?
4. What is Kafka partition key?
5. How many Kafka partitions is too many?
6. Can we increase Kafka partitions?
7. Why is Kafka partition needed?
8. Can Kafka have multiple consumers?
9. How many topics can Kafka support?
10. How do I view Kafka partitions?
11. Can Kafka run without zookeeper?
12. How do I read a specific partition in Kafka?

How many partitions should a Kafka topic have?

For most implementations you want to follow the rule of thumb of 10 partitions per topic, and 10,000 partitions per Kafka cluster. Going beyond that amount can require additional monitoring and optimization.

How does Kafka producer decide partition?

Kafka producer and partitions

1. Just specify it in the ProducerRecord itself.
2. If key is not null, (by default) Kafka will hash your key and calculate the partition.
3. If key is null, (by default) Kafka will round-robin b/w all the partitions (to load balance the data)
4. If not, just use a custom Partitioner.

How are partitions assigned in Kafka?

Finally, for each topic, the partitions are assigned starting from the first consumer . As you can seen, partitions 0 from topics A and B are assigned to the same consumer. In the example, at most two consumers are used because we have maximum of two partitions per topic .

What is Kafka partition key?

A key-value pair in a messaging system like Kafka might sound odd, but the key is used for intelligent and efficient data distribution within a cluster. Depending on the key, Kafka sends the data to a specific partition and ensures that its replicated as well (as per config). Thus, each record.

How many Kafka partitions is too many?

As guideline for optimal performance, you should not have more than 4000 partitions per broker and not more than 200,000 partitions in a cluster.

Can we increase Kafka partitions?

Apache Kafka provides us with alter command to change Topic behaviour and add/modify configurations. We will be using alter command to add more partitions to an existing Topic. Note: While Kafka allows us to add more partitions, it is NOT possible to decrease number of partitions of a Topic.

Why is Kafka partition needed?

Partitions are spread across the nodes in a Kafka cluster. ... Partitions can have copies to increase durability and availability and enable Kafka to failover to a broker with a replica of the partition if the broker with the leader partition fails. This is called the Replication Factor and can be 1 or more.

Can Kafka have multiple consumers?

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.

How many topics can Kafka support?

The rule of thumb is that the number of Kafka topics can be in the thousands. Jun Rao (Kafka committer; now at Confluent but he was formerly in LinkedIn's Kafka team) wrote: At LinkedIn, our largest cluster has more than 2K topics. 5K topics should be fine.

How do I view Kafka partitions?

1. Stream kafka-topics describe output for the given topics of interest.
2. Extract only the first line for each topic which contains the partition count and replication factor.
3. Multiply PartitionCount by ReplicationFactor to get total partitions for the topic.
4. Sum all counts and print total.

Can Kafka run without zookeeper?

You can not use kafka without zookeeper. ... So zookeeper is used to elect one controller from the brokers. Zookeeper also manages the status of the brokers, which broker is alive or dead. Zookeeper also manages all the topics configuration, which topic contains which partitions etc.

How do I read a specific partition in Kafka?

Try it

1. Initialize the project. ...
2. Get Confluent Platform. ...
3. Create a topic with multiple partitions. ...
4. Produce records with keys and values. ...
5. Start a console consumer to read from the first partition. ...
6. Start a console consumer to read from the second partition. ...
7. Read records starting from a specific offset. ...
8. Clean up.