Timedata Aggregated InfluxDB

OpenEMS Backend implementation for aggregated InfluxDB access.

A large number of OpenEMS edges connected to a single backend leads to a performance bottleneck. The bottleneck is mainly due to the access to the database. This Aggregated InfluxDB bundle in combination with the Timedata Influx bundle can mitigate this bottleneck. This happens by writing all data as usual via Timedata Influx into an Influx database (DB 1). Furthermore, all "aggregated data" (see edge datatypes) are written via the Aggregated InfluxDB bundle to another database (DB 2) located on another server. Thus DB 1 holds all data in high resolution, while DB 2 only holds very few data (5-minute averages for power values or only daily values for energy). Furthermore, a retention policy of e.g. 90 days is applied to DB 2. Thus DB 1 provides relatively slow access to a huge amount of data and DB 2 provides fast and responsive access to a relatively small database.

Within OpenEMS backend access to both databases is managed by the TimedataManager. The TimedataManager writes edge relevant data to all Timedata providers, whereas it reads data only from the first Timedata provider, which can deliver. Assuming correct configuration, TimedataManager first returns historical data from DB 2 (fast and responsive). And only in a very few cases it gets the data from DB 1 (probably slower).