Wide-column stores handle massive datasets:
How they work: Data organized by column families. Each row can have different columns. No schema enforcement.
Examples:
- Cassandra: Distributed, no single point of failure
- HBase: Runs on Hadoop, good for analytics
- Google Bigtable: Managed, powers many Google services
When to use: Time-series data, logs, IoT sensors. Wide-column stores work well at petabyte scale with predictable access patterns.
Trade-offs: Queries must be designed upfront. Ad-hoc queries are difficult. Limited secondary index support.