# `Prometheus` Introduction
+ `Prometheus` is an open source monitoring and alerting toolkit that includes a time series DB
  + Supports multi-dimensional data model
  + Supports flexible query language
+ `TiDB` uses the following components of `Prometheus`
  + The `Prometheus Server` to scrape and store metrics
  + The client libraries to customize necessary metrics in the application
  + An `Alert Manager` for the alerting mechanism
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As a time series database, `Prometheus` has a multi-dimensional data model and flexible query language. As one of the most popular open source projects, `Prometheus` has been adopted by many companies and organizations and has a very active community. `PingCAP` is one of the active developers and adopters of `Prometheus` for monitoring and alerting in `TiDB`, `TiKV` and `PD`.

`Prometheus` consists of multiple components. Currently, `TiDB` uses the following of them:
- The `Prometheus Server` to scrape and store metrics.
- The client libraries to customize necessary metrics in the application.
- An `Alert Manager` for the alerting mechanism.