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Current state: "Under Discussion"

Discussion thread: TODO [DISCUSS] KIP-591: Add Kafka Streams config to set default store type

JIRA:

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Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

Kafka Streams supports persistent RocksDB stores as well as in-memory stores out of the box. By default all DSL operators use persistent RocksDB stores. Currently, it is only possible to switch out RocksDB stores with in-memory store on a per operator basis what is tedious if all stores should be switched (for example in a Kubernetes deployment without local disks). Furthermore, the current store interface via Materialized is very generic as it allows to pass in any custom state store implementation with the side effect that a user needs to name the store and thus also makes it queryable via "Interactive Queries".

We propose to simplify switching the store type via a new config to Kafka Streams that allows to set the default store type for the whole program as well as an improved API for Materialized.

Public Interfaces

We propose to add a new configuration parameter default.dsl.store.type that defines the default store type used by the DSL accepting two values "rocksDB"  (default) and "in_memory" .

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