Problem with persistence and graphic

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(Tommaso Conti) #3

How can I make it happen more fast, like every second, or every half minute?

(Tommaso Conti) #4

I have already read this document but I didn’t find nothing about on every time store the value

(Daniel Walters) #5

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.

(Tommaso Conti) #6

What can I used instead of rrd4j?

(Harry) #7

The strategy everyMinute must be used, otherwise no data will be persisted (stored).

(Tommaso Conti) #8

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?

(Harry) #9

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.

(Tommaso Conti) #10

i am already using rrd4j and its ok, but I need to store a value every 1 or 10 seconds

(Vincent Regaud) #11


(Tommaso Conti) #13

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.

(Daniel Walters) #14

InfluxDB, MySQL/Maria, MongoDB etc may all be able to do that but you need to read the documentation accordingly and make your choice.

(Vincent Regaud) #15

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

(Tommaso Conti) #16

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.

(Tommaso Conti) #17

I’m going to see them. Thank you

(Tommaso Conti) #18

the persistence you listed me are all based on cloud services. I need them to be saved on the raspberry

(Harry) #19

Not right. You get the notice as soon as the device send it via MQTT.

(Vincent Regaud) #20

Incorrect, you can install influxdb on the PI.
Again, the pi SD card will wear down with rapid db updates

(Tommaso Conti) #21

ok, I know it, but I need to see it on the graph

(Vincent Regaud) #22

And you can graph it too… with GRafana

(Tommaso Conti) #23

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?