Eventual vs strong consistency in distributed databases

  • Ensure you replicate data for storage - in the case of databases, redundancy introduces reliability.
  • For consistency across multiple database replicas, a write request to any node should trigger write requests for all replicas.
  • In an ‘eventual consistency’ model, you can achieve low latency for read requests by delaying the updates to replicas, but you will risk returning stale data to read requests from some nodes if the update has not reached them yet.
  • With a ‘strong consistency’ model, write requests to replicas will be triggered immediately. However, they will delay subsequent read/write requests to any of the databases until the consistency is reached.

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