When should I use Redis instead of ScyllaDB?

Ultra-low-latency caching and session storage with sub-millisecond read and write times. Message brokering via Pub/Sub or Redis Streams for simple event-driven workloads. Leaderboards, rate limiting, and real-time counters using atomic data structures

When should I use ScyllaDB instead of Redis?

High-performance Cassandra-compatible wide-column store with lower latency via C++ implementation. Teams wanting Cassandra semantics with better throughput and without JVM GC pause latency spikes. Workloads where Cassandra's JVM garbage collection causes unpredictable tail latency

What are the main weaknesses of Redis?

Data must fit in RAM — not suitable as a primary store for large datasets. Persistence options (RDB snapshots, AOF) add latency or disk I/O overhead. License changed to RSALv2/SSPL in v7.4; Valkey is the open-source fork maintained by the community

What are the main weaknesses of ScyllaDB?

Cassandra compatibility is not 100%; subtle behavioral differences can surface during migration. Smaller community and ecosystem than Apache Cassandra for tooling and integrations. Self-managed deployment requires Cassandra operational expertise plus ScyllaDB-specific knowledge

Redis vs ScyllaDB: Key Differences for Python Data Engineering

Databases & Data Warehouses

Redis

In-Memory Data Store

★ 4.7

RSALv2 / SSPL (v7.4+)

pip install redis

ScyllaDB

High-Performance Cassandra Alternative

★ 4.5

AGPL-3.0 (Community)

pip install scylla-driver

Side-by-Side Comparison

Redis

ScyllaDB

Redis

ScyllaDB

Best For

✓Ultra-low-latency caching and session storage with sub-millisecond read and write times
✓Message brokering via Pub/Sub or Redis Streams for simple event-driven workloads
✓Leaderboards, rate limiting, and real-time counters using atomic data structures

✓High-performance Cassandra-compatible wide-column store with lower latency via C++ implementation
✓Teams wanting Cassandra semantics with better throughput and without JVM GC pause latency spikes
✓Workloads where Cassandra's JVM garbage collection causes unpredictable tail latency

Best For

✓Ultra-low-latency caching and session storage with sub-millisecond read and write times
✓Message brokering via Pub/Sub or Redis Streams for simple event-driven workloads
✓Leaderboards, rate limiting, and real-time counters using atomic data structures

✓High-performance Cassandra-compatible wide-column store with lower latency via C++ implementation
✓Teams wanting Cassandra semantics with better throughput and without JVM GC pause latency spikes
✓Workloads where Cassandra's JVM garbage collection causes unpredictable tail latency

Weaknesses

•Data must fit in RAM — not suitable as a primary store for large datasets
•Persistence options (RDB snapshots, AOF) add latency or disk I/O overhead
•License changed to RSALv2/SSPL in v7.4; Valkey is the open-source fork maintained by the community

•Cassandra compatibility is not 100%; subtle behavioral differences can surface during migration
•Smaller community and ecosystem than Apache Cassandra for tooling and integrations
•Self-managed deployment requires Cassandra operational expertise plus ScyllaDB-specific knowledge

Weaknesses

•Data must fit in RAM — not suitable as a primary store for large datasets
•Persistence options (RDB snapshots, AOF) add latency or disk I/O overhead
•License changed to RSALv2/SSPL in v7.4; Valkey is the open-source fork maintained by the community

•Cassandra compatibility is not 100%; subtle behavioral differences can surface during migration
•Smaller community and ecosystem than Apache Cassandra for tooling and integrations
•Self-managed deployment requires Cassandra operational expertise plus ScyllaDB-specific knowledge

License

RSALv2 / SSPL (v7.4+)

AGPL-3.0 (Community)

License

RSALv2 / SSPL (v7.4+)

AGPL-3.0 (Community)

Install

pip install redis

pip install scylla-driver

Install

pip install redis

pip install scylla-driver

Rating

★ 4.7

★ 4.5

Rating

★ 4.7

★ 4.5

Key Features

Redis

1Sub-millisecond read/write latency for in-memory data structures
2Support for strings, hashes, lists, sets, sorted sets, streams, and more
3Pub/Sub messaging and Redis Streams for event-driven pipeline patterns
4Built-in TTL expiry for automatic cache invalidation
5Redis Cluster for horizontal scaling and high availability

ScyllaDB

1Cassandra-compatible NoSQL database written in C++ for 10x lower latency
2Shard-per-core architecture eliminates cross-core synchronization overhead
3Drop-in Cassandra replacement — uses the same CQL and drivers
4Compaction strategies optimized for write-heavy workloads
5ScyllaDB Cloud for fully managed deployment on AWS, GCP, and Azure

How Python Data Engineers Use These Tools

Redis

Python data engineers use Redis via the redis-py library as a high-speed caching layer, rate-limit store, and task queue broker. Redis is the default broker for Celery-based task queues and is used by Apache Airflow for caching pipeline metadata. In data pipelines, Redis stores intermediate results, deduplication sets, and real-time leaderboards that would be too slow to query from a relational database on every request.

ScyllaDB

Python data engineers use ScyllaDB as a Cassandra replacement when latency is critical — the `cassandra-driver` library works unchanged since ScyllaDB is wire-compatible. Engineers migrating from Cassandra to ScyllaDB typically see P99 write latency drop from milliseconds to microseconds without any Python code changes.

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Individual Tool Pages

View Redis details →View ScyllaDB details →

Side-by-Side Comparison

Redis

ScyllaDB

Redis

ScyllaDB

Best For

✓Ultra-low-latency caching and session storage with sub-millisecond read and write times
✓Message brokering via Pub/Sub or Redis Streams for simple event-driven workloads
✓Leaderboards, rate limiting, and real-time counters using atomic data structures

✓High-performance Cassandra-compatible wide-column store with lower latency via C++ implementation
✓Teams wanting Cassandra semantics with better throughput and without JVM GC pause latency spikes
✓Workloads where Cassandra's JVM garbage collection causes unpredictable tail latency

Best For

✓Ultra-low-latency caching and session storage with sub-millisecond read and write times
✓Message brokering via Pub/Sub or Redis Streams for simple event-driven workloads
✓Leaderboards, rate limiting, and real-time counters using atomic data structures

✓High-performance Cassandra-compatible wide-column store with lower latency via C++ implementation
✓Teams wanting Cassandra semantics with better throughput and without JVM GC pause latency spikes
✓Workloads where Cassandra's JVM garbage collection causes unpredictable tail latency

Weaknesses

•Data must fit in RAM — not suitable as a primary store for large datasets
•Persistence options (RDB snapshots, AOF) add latency or disk I/O overhead
•License changed to RSALv2/SSPL in v7.4; Valkey is the open-source fork maintained by the community

•Cassandra compatibility is not 100%; subtle behavioral differences can surface during migration
•Smaller community and ecosystem than Apache Cassandra for tooling and integrations
•Self-managed deployment requires Cassandra operational expertise plus ScyllaDB-specific knowledge

Weaknesses

•Data must fit in RAM — not suitable as a primary store for large datasets
•Persistence options (RDB snapshots, AOF) add latency or disk I/O overhead
•License changed to RSALv2/SSPL in v7.4; Valkey is the open-source fork maintained by the community

•Cassandra compatibility is not 100%; subtle behavioral differences can surface during migration
•Smaller community and ecosystem than Apache Cassandra for tooling and integrations
•Self-managed deployment requires Cassandra operational expertise plus ScyllaDB-specific knowledge

License

RSALv2 / SSPL (v7.4+)

AGPL-3.0 (Community)

License

RSALv2 / SSPL (v7.4+)

AGPL-3.0 (Community)

Install

pip install redis

pip install scylla-driver

Install

pip install redis

pip install scylla-driver

Rating

★ 4.7

★ 4.5

Rating

★ 4.7

★ 4.5

Key Features

Redis

1Sub-millisecond read/write latency for in-memory data structures
2Support for strings, hashes, lists, sets, sorted sets, streams, and more
3Pub/Sub messaging and Redis Streams for event-driven pipeline patterns
4Built-in TTL expiry for automatic cache invalidation
5Redis Cluster for horizontal scaling and high availability

ScyllaDB

1Cassandra-compatible NoSQL database written in C++ for 10x lower latency
2Shard-per-core architecture eliminates cross-core synchronization overhead
3Drop-in Cassandra replacement — uses the same CQL and drivers
4Compaction strategies optimized for write-heavy workloads
5ScyllaDB Cloud for fully managed deployment on AWS, GCP, and Azure

How Python Data Engineers Use These Tools