From 23fa5ee510503ffaaf031e6ba3b55efef0c47ecd Mon Sep 17 00:00:00 2001 From: Wouter Born Date: Thu, 15 Dec 2022 23:20:30 +0100 Subject: [PATCH] [mapdb] Add some documentation This is based on the original OH1 documentation. Signed-off-by: Wouter Born --- bundles/org.openhab.persistence.mapdb/README.md | 12 ++++++++++++ 1 file changed, 12 insertions(+) create mode 100644 bundles/org.openhab.persistence.mapdb/README.md diff --git a/bundles/org.openhab.persistence.mapdb/README.md b/bundles/org.openhab.persistence.mapdb/README.md new file mode 100644 index 0000000000000..d1d972fcd1817 --- /dev/null +++ b/bundles/org.openhab.persistence.mapdb/README.md @@ -0,0 +1,12 @@ +# MapDB Persistence + +The [MapDB](https://mapdb.org/) persistence service is based on 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.