Hi Folks, for my project I need to be able to go back in time and access a small set of previously collected senor data values. The set is quite small, about 10 - 25 values, The values are collected over a period of the last 10 days from now. The important value for my event/flow is the minimum …

If you have no need to go back and see the historical data, You can use the Context to store the min value https://nodered.org/docs/writing-functions#storing-data Why over complicate things?

and that context can be persistent over restarts if you wish. [image] A guide to understanding 'Persistent Context' General This is something I wrote up after playing with the context options. I've filed a PR with some of this added to the Node-RED documentation but though…

....that sounds perfect, thank you both for the fast response. @ukmoose , you are right, thought about that, too...but I see the need to access the historic data as part of my use case. The min-value alone might not be sufficient and some re-calculations need to be done from the historical data. @d…

If you decide that you want a complete (or longer) historical data set then have a look at influxdb.

[image] hominidae: I see the need to access the historic data How often are you getting updated values? That makes a massive difference. 25 x 10 x 17280 = 4,320,000 entries! (25 sensors, 10 days, updates every 5 seconds) 25 x 10 x 1440 = 360,000 entries (updates every minute) That drops to…

Just using a File node is super simple and easy to set up. I run many, using them as backups (to Influx) of the raw data that come from devices. Using a Function node you can customise the output for easy import into Excel or whatever. All the data is collected on an ssd which hangs directly off th…

Thanks for the info, @TotallyInformation ...very good calculation of the amount of data which sensors could produce. However my use case is a bit different. There will be only one, maybe two (temperature-) sensors, pushing data every minute. What I need to actually collect and access is just the…

...nice idea @Bobo , to backup the raw data using File node(s)...thanks for sharing

[image] hominidae: What I need to actually collect and access is just the minimum values, reached over the last 5 days, which are approx. 10-25 values in total (per sensor). A minimum value is defined as the temperature that has been previously collected before another, newer-in-time value is h…

[image] TotallyInformation: you should still try using InfluxDB and Grafana I second that. Also, the Grafana Charts are super nice!

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Best way to collect, store and retrieve a small (10-25) set of sensor values

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dceejay 6 April 2019 14:48 3

and that context can be persistent over restarts if you wish.

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Best way to collect, store and retrieve a small (10-25) set of sensor values

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