We have a sound like signal which we have transformed with FFT to form an array of values. This array is for us a logical single data point / measurement.
How would you recommend storing this data in influxdb (or do you recommend). The data itself is timeseries data and the time when it was taken is important. We are anyway going to use influxdb for storing single dimensional kpi values calculated from the same original data.
Correct, InfluxDB does not support array field types. InfluxDB v2, the following field types are supported:
string
float
integer
unsigned integer
boolean
These are the primary two methods I could think of as well, but they both have downsides.
Storing data as comma-separated string: This would be cumbersome and wouldn’t compress well over time, so, depending on the retention period for this data, storage will get more expensive over time. However, with Flux, you can convert the comma-separated string into an array at query time and operate on it as an array.
Storing the data within x fields: This would be very cumbersome to query and would result in very high cardinality. In InfluxDB Cloud, the field key is part of the series key, so the more fields you have, the higher the cardinality of your data. InfluxDB Cloud limits cardinality based on your subscription plan:
Free plan: 10k series cardinality
Usage-based plan: 1m series cardinality
The only other thing I can really think of is storing these arrays externally, but somehow be able to reference them through an API. That way, you could store a reference key as a field in InfluxDB and then map the arrays in at query time using the reference key. The downside here is that will add a lot of latency to your queries as those values are mapped in row by row.
