A Review Of 100% Correct CCDAK Exam Prep

session.timeout.ms must be decreased to 3 seconds to allow for a faster rebalance, and the heartbeat thread must be quicker, so we also need to decrease heartbeat.interval.ms

All brokers can respond to Metadata request, so a client can connect to any broker in the cluster.

subscribe() and assign() cannot be called by the same consumer, subscribe() is used to leverage the consumer group mechanism, while assign() is used to manually control partition assignment and reads assignment

acks is a producer setting min.insync.replicas is a topic or broker setting and is only effective when acks=all

Clients with new schema will be able to read records saved with old schema.

Mostly-static data is modeled as a table whereas business transactions should be modeled as a stream.

Clients with old schema will be able to read records saved with new schema.

With SSL, messages will need to be encrypted and decrypted, by being first loaded into the JVM, so you lose the zero copy optimization. See more information herehttps://twitter.com/ijuma/status/1161303431501324293?s=09

This will allow consumers to wait and receive more bytes in each fetch request.

Each consumer is assigned a different partition of the topic to consume.

SHOW STREAMS and EXPLAIN <query> statements run against the KSQL server that the KSQL client is connected to. They don't communicate directly with Kafka. CREATE STREAM WITH <topic> and CREATE TABLE WITH <topic> write metadata to the KSQL command topic. Persistent queries based on CREATE STREAM AS SELECT and CREATE TABLE AS SELECT read and write to Kafka topics. Non-persistent queries based on SELECT that are stateless only read from Kafka topics, for example SELECT … FROM foo WHERE …. Non-persistent queries that are stateful read and write to Kafka, for example, COUNT and JOIN. The data in Kafka is deleted automatically when you terminate the query with CTRL-C.

The REST Proxy requires to receive data over REST that is already base64 encoded, hence it is the responsibility of the producer

Preferred leader is a broker that was leader when topic was created. It is preferred because when partitions are first created, the leaders are balanced between brokers. Otherwise, any of the in-sync replicas (ISR) will be elected leader, as long as unclean.leader.election=false (by default)

Some messages may require multiple retries. If there are more than 1 requests in flight, it may result in messages received out of order. Note an exception to this rule is if you enable the producer settingenable.idempotence=true which takes care of the out of ordering case on its own. Seehttps://issues.apache.org/jira/browse/KAFKA-5494

ACLs are stored in Zookeeper node /kafka-acls/ by default.

Protocol buffers isn't a natively supported type for the Confluent REST Proxy, but you may use the binary format instead

Point-to-point (request-response) style will couple client to the server.

Examplekafka-console-consumer --bootstrap-server 127.0.0.1:9092 --topic test --from- beginning

Setting a group.id that's consistent across restarts will allow your consumers part of the same group to resume reading from where offsets were last committed for that group

Kafka's new bidirectional client compatibility introduced in 0.10.2 allows this. Read more herehttps://www.confluent.io/blog/upgrading-apache-kafka-clients-just-got-easier/

When you create a new topic, partitions replicas are spreads across racks to maintain availability. Hence, the Rack A, which currently does not hold the topic partition, will be selected for the last replica

In case of KStream-KStream join, both need to be co-partitioned. This restriction is not applicable in case of join with GlobalKTable, which is the most efficient here.

Seehttps://kafka.apache.org/21/javadoc/org/apache/kafka/clients/producer/KafkaProducer. html

You will need to set the schemas.enable parameters for the converter to false for plain text with no schema.

Kafka transfers data with zero copy and no transformation. Any transformation (including compression) is the responsibility of clients.

In case the consumer has the wrong leader of a partition, it will issue a metadata request. The Metadata request can be handled by any node, so clients know afterwards which broker are the designated leader for the topic partitions. Produce and consume requests can only be sent to the node hosting partition leader.

Replicas are passive - they don't handle produce or consume request. Produce and consume requests get sent to the node hosting partition leader.

Controller is a broker that in addition to usual broker functions is responsible for partition leader election. The election of that broker happens thanks to Zookeeper and at any time only one broker can be a controller

If more than one similar config is specified, the smaller unit size will take precedence.

Both key and value serializer are mandatory.

None

Consumers can set auto.offset.reset property to earliest to start consuming from beginning. For KSQL, SET 'auto.offset.reset'='earliest';

A kafka broker automatically creates a topic under the following circumstances- When a producer starts writing messages to the topic - When a consumer starts reading messages from the topic - When any client requests metadata for the topic

metadata is stored in and built from the KSQL command topic. Each KSQL server has its own in-memory version of the metastore.