CCDAK Exam Dumps - Confluent Certified Developer for Apache Kafka Certification Examination

There is only one controller in a cluster at all times.

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

Kafka Connect Sink is used to export data from Kafka to external databases and Kafka Connect Source is used to import from external databases into Kafka.

Aggregations of stream are stored in table, whereas Streams must be modeled as a KStream to avoid data explosion

Producer idempotence helps prevent the network introduced duplicates. More details herehttps://cwiki.apache.org/confluence/display/KAFKA/Idempotent+Producer

See https://stackoverflow.com/a/37748336/3019499

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

Kafka topics are divided into partitions and spread across brokers. Each brokers knows about all the metadata and each broker is a bootstrap broker, but only one of them is elected controller

A hopping window is defined by two propertiesthe window's size and its advance interval (aka "hop"), e.g., a hopping window with a size 5 minutes and an advance interval of 1 minute.

The high watermark is an advanced Kafka concept, and is advanced once all the ISR replicates the latest offsets. A consumer can only read up to the value of the High Watermark (which can be less than the highest offset, in the case of acks=1)

In Kafka, a small heap size is needed, while the rest of the RAM goes automatically to the page cache (managed by the OS). The heap size goes slightly up if you need to enable SSL

Increasing the number of partition causes new messages keys to get hashed differently, and breaks the guarantee "same keys goes to the same partition". Kafka logs are immutable and the previous messages are not re-shuffled.

Replicas are spread across available brokers, and each replica = one broker. RF 3 = 3 brokers

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

Partitions for newly created topics are assigned in a rack alternating manner, this is the only change broker.rack does

Latest means that data retrievals will start from where the offsets currently end

With this configuration, a single in-sync replica is still readable, but not writeable if the producer using acks=all

Sending a message with the null value is called a tombstone in Kafka and will ensure the log compacted topic does not contain any messages with the key K upon compaction

Dynamic topic configurations are maintained in Zookeeper.