Which is the recommended min.delay to dynamically add points to a line chart ? In our test-case an embedded device is publishing mqtt messages which are visualized in a line chart on a node-red dashboard. When the device publishes faster than each 500 milliseconds (for instance each 250 msec or eve…

The bottleneck is number of points the chart has to calculate and render. For every new incoming data all the points "move" and amount of job needed to be done increases. Second thing is reasonable amount of data points to present. You cant actually fit two points into one pixel. Chart becomes unrea…

Would be eventually better to write a function that "caches" the mqtt data as a kind of ring-buffer (for instance the last 100 or 1000 values from the embedded device) and override the complete line chart each time when new data arrives ?

This is one of many many options of course. You'll get rid of excessive rendering calls.

Approximately how wide is your chart and what time range have you specified it should display over?

The sample rate for the chart should be something between 100 and 250 msec. We would like to display like the last 30-40 seconds (so the chart could contain about 300-400 points). What would be the best way to integrate in a node-red flow some custom javascript functions that handle a ring buffer ? …

For something like this I would not attempt to use the node-red chart, I suggest you could be better looking at influxdb for the data storage and grafana for the charts. They are both designed for high performance operating with real time data.

@Colin Thank you for the information. Where can be found some good samples about using grafana charts (with or without influxdb) with the node-red dashboard? Is it possible to use also another data-source for the grafana chart, for instance my custom ring-buffer (still have the open question about…

[image] abra: I think that influxdb is maybe an overkill for my application. Does influxdb run also on windows? Is it free also for commercial projects? It is not intensive on resources, I run it on a RPi though at nothing like the data rate you want. On the other hand if you only ever want …

[image] abra: custom ring-buffer Searching the flows site yields node-red-contrib-buffer-array (node) - Node-RED which may be what you want.

Thanks again. Yes, actually I am looking for a chart to visualize current (realtime) data.

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Line chart performance

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Line chart performance

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