[manigandham]

ElasticSearch is a database optimized for searching, not related at all.

You can somewhat compare Kafka to Logstash but Kafka has no processing, it's purely a distributed log writing/reading/storage system that also scales far more than logstash can. You write data to it and then read from it with a basic messaging abstraction of topics and partitions.

[ec109685]

ElasticSearch can store sequenced number data, which is really all that Kafka is doing, so I don't think it is fair to say it isn't related at all.

[allengeorge]

So can a RDBMS... But that doesn't mean that Kafka and databases are related.

As multiple comments have stated above, Kafka is really a distributed message subsystem. Its core interface is a set of topics that one can publish to, and that consumers can read from (in other words, a pub-sub system). Kafka doesn't inspect the message payload at all.

Elasticsearch is a unstructured (to some extent) document store that's optimized around document search. So at the very least, the payload is important when using Elasticsearch.

[manigandham]

That's like saying they all write data to disk so they're related.

Elasticsearch is all about saving, inspecting, indexing and retrieving your data through a rich document-based model and search-optimized methods.

ES might be able to do the same thing functionally because it operates at a higher level but ultimately will never scale or be as simple in access as Kafka.