Tag: sql

MariaDB/SQL query gotcha and optimized solution (#E19)

Haven’t had a general advice post for a while, have we.

My small fleet of ESP32 boards across the apartment is still gathering information for the AVM Fritz DECT 301 radiator control units that just started the heating season. While their queries are really simple, quick and fully automated, I also have an HighCharts overview plot of all data with user-defined query depth, usually 300 minutes / 5 hours, but I think there’s no arbitrary limit to it. One could plot all 2 million rows of data…but I’m not gonna try.

Anyway, I recently noticed query times went up significantly, and the whole thing never was blazing fast in the first place. […]


DHT22 WiFi (ESP8266) temperature/humidity loggers (#P7)

Guess who was busy and also did not prepare a post in advance? Yeah, lazy me :mrgreen:

Well, let’s pick up some project that I’m deploying slowly around my flat. I intend to run five of these devices, one with some light meter and maybe other outdoor sensors, the others will be indoors. I’ve been running the early prototype for quite some while now, doubling as a Blynk gateway to some LED strips in the liquor cabinet (yeah, I called it Boozy McBoozeface for a reason). Accessing lights at home from far away isn’t that important to me, so once I have time to install some more touch buttons, that one will be no longer running Blynk, probably eliminating some timing/connectivity issues. […]