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Databases & search
Wide-column database
Write-optimised partitioned store for huge append-heavy datasets.
When to use
- Messages, timelines, view history, time-ordered events
Pitfalls
- Partition key choice decides everything; hot partitions hurt
Options by provider
The first option is what diagrams show for that provider.
Amazon Web Services
- Amazon KeyspacesManaged
- Amazon DynamoDBManaged
Google Cloud
- BigtableManaged
Microsoft Azure
- Azure Cosmos DB for Apache CassandraManaged
Open source / self-hosted
- Apache CassandraSelf-hosted
- ScyllaDBSelf-hosted
- HBaseSelf-hosted
Related concepts
Used in
- YouTube
- Metadata DB — Videos, comments and likes, partitioned by videoId
- Netflix
- Viewing history (Cassandra) — Every profile's watch progress
- Instagram
- Likes & comments — High-volume activity per post
- Twitter / X
- Tweet store — All tweets, plus a per-author index
- WhatsApp / Messenger
- Message store — Every message, partitioned by conversation
- Web crawler
- URL metadata — Status and schedule for every known URL
- Quora
- Votes & activity — High-volume activity
- LinkedIn
- Posts — Member posts and activity