openhab-addons/bundles/org.openhab.persistence.mapdb/README.md

# MapDB Persistence

The [MapDB](https://mapdb.org/) persistence service is based on a simple key-value store that only saves the last value.
MapDB is useful for restoring items that have the `restoreOnStartup` strategy because other persistence options have some drawbacks if only the last value is needed on restarts.

Some disadvantages of other persistence services compared to MapDB are that they:

- grow in time
- require complex installs (`influxdb`, `jdbc`, `jpa`)
- `rrd4j` cannot store all item types (only numeric types)

It is only possible to query the last value and not other historic values because the MapDB persistence service can only store one value per item.
[mapdb] Add some documentation (#13964) This is based on the original OH1 documentation. Signed-off-by: Wouter Born <github@maindrain.net> 2022-12-15 23:39:37 +01:00			`# MapDB Persistence`

[mapdb] Fix "a" typo and use "-" for bullets in docs (#13966) Signed-off-by: Wouter Born <github@maindrain.net> 2022-12-16 11:22:48 +01:00			`The [MapDB](https://mapdb.org/) persistence service is based on a simple key-value store that only saves the last value.`
[mapdb] Add some documentation (#13964) This is based on the original OH1 documentation. Signed-off-by: Wouter Born <github@maindrain.net> 2022-12-15 23:39:37 +01:00			MapDB is useful for restoring items that have the `restoreOnStartup` strategy because other persistence options have some drawbacks if only the last value is needed on restarts.

			`Some disadvantages of other persistence services compared to MapDB are that they:`

[mapdb] Fix "a" typo and use "-" for bullets in docs (#13966) Signed-off-by: Wouter Born <github@maindrain.net> 2022-12-16 11:22:48 +01:00			`- grow in time`
			- require complex installs (`influxdb`, `jdbc`, `jpa`)
			- `rrd4j` cannot store all item types (only numeric types)
[mapdb] Add some documentation (#13964) This is based on the original OH1 documentation. Signed-off-by: Wouter Born <github@maindrain.net> 2022-12-15 23:39:37 +01:00
			`It is only possible to query the last value and not other historic values because the MapDB persistence service can only store one value per item.`