# Key concepts

## Storage types

Marple DB is a highly optimised data storage solution. It mainly targets high-frequency time series data obtained with measurement files. To optimise cost and performance, it combines three types of storage in a seamless way:

1. **Hot storage** (PostgreSQL)
2. **Cold storage** (Parquet on Apache Iceberg)
3. **Archive storage** (Object storage)

<figure><img src="https://3590686807-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FwEBNWlmdcxXBXd7oyqyR%2Fuploads%2FwSWfOCjL03GXa7Fa9VMA%2Fmarple-db-storage-types.png?alt=media&#x26;token=f8ee514e-5e43-4cd9-b21b-5a046929dcc1" alt=""><figcaption></figcaption></figure>

Marple DB automatically handles loading individual signals from cold storage to hot when needed. Lifecycle rules can be used to transition from cold to archive.

## Datastream

Marple DB can consume data from different sources. A datastream allows you to configure

* The file plugin (see below)
* [preprocessing-rules](https://docs.marpledata.com/docs/marple-db/datastreams/preprocessing-rules "mention") rules
* A unified name space (UNS)
* Automations

Read more in [datastreams](https://docs.marpledata.com/docs/marple-db/datastreams "mention")

## Plugin

Data files exist in a lot of different file types (CSV, MDF, MAT, HDF5, ...). A plugin is a software module that reads out the data & metadata for a specific file type.

Read more in [supported-file-types](https://docs.marpledata.com/docs/marple-db/datastreams/supported-file-types "mention")

## Datapool

A datastream writes its data into a datapool, which defines the Postgres tables where data will be written to.

By default, all datastreams write into the same `default` datapool. Changing this is for advanced use cases.

## Discover Marple DB in 1 minute

{% embed url="<https://www.youtube.com/watch?index=27&list=PLtVuqpI9QpJAFtUEvuS23Z47XGHrRc_P9&v=m0msNW6tSHU>" %}

Want to discover other Marple features in 1 minute? Check out other [1-minute-marple-videos](https://docs.marpledata.com/docs/other-resources/1-minute-marple-videos "mention")