Time series databases are optimized for storing time-stamped sensor or event data in regular intervals, with little change to stored values. They differ from relational databases by using column-oriented storage, indexing time as a key, and supporting high write volumes, automatic data compaction, and continuous queries over aggregated time series data. Examples include InfluxDB, which uses a time-structured merge tree to optimize storage of billions of data points within a low disk footprint. While time series databases excel at certain use cases, relational databases may still be better for other types of complex, non-time-based data.