Historical data, own server - default feature, or DB needed?

[sydowski]

Hi,
I recently set up my own local Blynk server on Raspberry Pi. Everything seems to work just fine as far, but I’m still waiting for new NodeMCU modules to begin exploring Your promising piece of software.

In the meantime, I was trying to find out how the historical data for graphs and supercharts is stored. Couldn’t find a clear answer, and this is my concern - is it essential to install and node PostgreSQL with Blynk server to unlock the feature of viewing historical data after the android app was closed i.e. all night? Or the raw data storage is needed only to export data as csv files?

I read somewhere, that superchart widgets store necessery data in .bin files, but how far in past is the data stored in this case? Is it stored when the phone app is closed?

Thanks for your time
Regards,
Sydowski

[Dmitriy]

Hello.

@sydowski

is it essential to install and node PostgreSQL with Blynk server to unlock the feature of viewing historical data after the android app was closed i.e. all night?

No. By default, all data is stored directly on disk without DB. Postgres is just additional option.

@sydowski

Or the raw data storage is needed only to export data as csv files?

No. It is needed to store EVERY value your hardware sends. Here is current implementation - Introduction - Blynk Documentation.

@sydowski

but how far in past is the data stored in this case?

All data is stored and those files are never cleaned. So in other words it stores data as long as you have disk space for it.

@sydowski

Is it stored when the phone app is closed?

Yes. The only exclusion - widget with Reading Period.

[sydowski]

Thanks, that is what I wanted to know