How can I make it happen more fast, like every second, or every half minute?
I have already read this document but I didn’t find nothing about on every time store the value
I don’t think you can - it sounds like one minute is as granular as you can get with rrd4j. So you may need to pick another persistence service if you require more a granular time series.
What can I used instead of rrd4j?
The strategy everyMinute must be used, otherwise no data will be persisted (stored).
ok, so I have understand that with rrd4j I can only store data at least 1 minute. If I want store data like every second, how can I do, also using other persistence?
I think rrd4j is a good way to store temperatue-values for a chart over a long time.
I would try and see if it works.
i am already using rrd4j and its ok, but I need to store a value every 1 or 10 seconds
because I need to put this temperature sensor in a controlled temperature room, and I need a graph very accurate that acquires data as fast as possible.
InfluxDB, MySQL/Maria, MongoDB etc may all be able to do that but you need to read the documentation accordingly and make your choice.
You can use any other database execpt mapdb which only stores the last value.
But our are talking about a room here not a formula 1 car. The temperature variations are not that fast.
Have a look at this:
But beware, the size of your DB will grow fast
Okok, I know that temperature doesn’t change so fast, but if the temperature in the room goes down 20° (for example) I will notice it only after a minute, too late for the circumstance.
I’m going to see them. Thank you
the persistence you listed me are all based on cloud services. I need them to be saved on the raspberry
Not right. You get the notice as soon as the device send it via MQTT.
Incorrect, you can install influxdb on the PI.
Again, the pi SD card will wear down with rapid db updates
ok, I know it, but I need to see it on the graph
And you can graph it too… with GRafana
My sd card is 64gb and the system I remember took only 10gb. So there is very large space. Anyhow, can I set that after a moth the previous data were delete?