Influx db persistence policies (default versus non default)

[luke101 (Vander Putten)]

Hi,

Just started with Influx-Grafana a week ago. All working quite well. To avoid running out of space I decided to create a retention policy:

As you can see, the creation was successful but when querying for policies on my openhab_db I see autogen is still default and next to my created one.

So my question is: What is the impact of having both autogen as default and a created policy? Will my policy work? Do I need to set it as default? How?

Thanks

Luc.

[sihui]

@luke101

To avoid running out of space

InfluxDB+Grafana persistence and graphing

Hello @ThomDietrich! Sorry for the delay, I really haven’t had any free time earlier to write this. I’ve done some research on InfluxDB database shrinking, and, if I understood the stuff I’ve read correctly, InfluxDB used numbers of storage engines over time (different from version to version - LevelDB, RocksDB, BoltDB), but the latest version (1.3 at the time of writing this) is using Time Structured Merge Tree (their own storage engine). This storage engine is shrinking data automatically, b…

InfluxDB Retention policy

You didn’t find it because there is no autogen file. This is the name of the default retention policy. The retention policy is configured with an influxdb admin tool (you can do this e.g. with chronograf) or the influx cli. Not sure if there also is a config file to do this. But more important: while you can have multiple retention policies for one database from influx side, the openhab binding supports just one retention policy. Means you can not choose to delete values earlier or later on a i…

[luke101 (Vander Putten)]

Hi @sihui. Txs for articles. I’ve read both articles before posting my question and they do not answer it.
I found in Influx db documentation that best way to set retention policy is to do so at database creation time because default retention policy cannot be changed.afterwards. Only additional policies can be added. To be honest I don’t know how several policies can coexist and it is not explained clearly for what purpose anyone would want concurrent policies.
To make a long story short, default (and only supported in OH?) policy must be specified at db creation time. Unfortunately in above original tutorial from @ThomDietrich
the suggested creation does not specify any retention policy and hence the default (infinite) retention is taken by default. May I suggest @ThomDietrich to update the creation exemple to include retention like in Influx 1.7 manual for InfluxQL data management:

CREATE DATABASE <database_name> [WITH [DURATION ] [REPLICATION ] [SHARD DURATION ] [NAME ]]

https://docs.influxdata.com/influxdb/v1.8/query_language/manage-database/

Best,
Luc.