Event Store vs Scylla: What are the differences?
Event Store and Scylla are two popular technologies used in the software industry for different purposes. In this analysis, we will outline the key differences between these two technologies.
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Database Model: Event Store is a type of database that follows an event sourcing model, where events are stored as a log in an append-only fashion. On the other hand, Scylla is a NoSQL database that uses a column-family data model, similar to Apache Cassandra.
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Data Consistency: Event Store provides strong consistency guarantees, ensuring that events are stored and processed in a specific order. It also supports optimistic concurrency control to handle concurrent writes. In contrast, Scylla offers eventual consistency, where data may temporarily diverge across replicas but eventually becomes consistent.
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Scalability and Performance: Scylla is designed for high performance and scalability, capable of handling large volumes of data and high throughput. It is optimized to leverage the hardware resources efficiently, making it a suitable choice for applications with demanding performance requirements. Event Store, while also scalable, is more focused on providing strong consistency guarantees and is often used in event-driven architectures.
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Query Capabilities: Scylla supports a wide range of queries using the Cassandra Query Language (CQL), including ad-hoc queries, range scans, and secondary indexes. It also provides support for aggregations and analytics through integration with Apache Spark. Event Store, on the other hand, is more specialized for event sourcing scenarios and provides specific query capabilities tailored for working with event streams.
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Data Durability: Both Event Store and Scylla ensure data durability by persisting data to disk. However, Event Store also offers a feature called "at-least-once delivery," which guarantees that events will be stored even if errors or failures occur during processing. This ensures that events are not lost in case of failures.
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Community and Ecosystem: Scylla benefits from its compatibility with the Apache Cassandra ecosystem. It can leverage existing tools, libraries, and community support, making it a popular choice for applications that require compatibility with Cassandra. Event Store, while also having an active community, has a smaller ecosystem and is more tailored for specific use cases.
In summary, Event Store is primarily intended for event sourcing scenarios, providing strong consistency guarantees, while Scylla focuses on scalability, performance, and compatibility with the Apache Cassandra ecosystem.