I configured my Home Assistant influxdb integration to log absolutely everything, but my InfluxDB database grew out of control.
After setting up proper filtering for the entities I really needed, I had to manually delete (drop) all the unwanted measurements.

First, I dumped all the measurements in a text file :

influx -database ha -username admin -execute "show measurements"

With the influx command line tool and a bit of bash scripting, I was able to send a InfluxQL command DROP MEASUREMENT, but often some measurement were not dropped (still displayed with « SHOW MEASUREMENTS », and sometimes still had some records.

This is a known issue and it won’t probably be fixed in versions 1.x.

Finally, I ended up writing a ‘quick and dirty » python script to drop the measurements listed in a text file.
It performs the following steps:

• Reads the measurement to drop, line by line, from a text file
• Issues a SHOW MEASUREMENT query, and iterates through the results until a match is found
• Tries to display the count of points found
• Executes the DROP MEASUREMENT query
• Attemps to to display the points count again  (but I never saw this happening) or, if the measurement is not found, considers it was successfully dropped

Ensure you have installed the influxdb pip package :

pip install influxdb

Here is the script :

import time
from influxdb import InfluxDBClient
client = InfluxDBClient('nas', 8086, 'admin', '', 'ha') 
file = open("//nas/data/ms-2025-01-04-delete.txt")
for line in file :
    ligne = line.strip()
    print()
    print("%s : " % ligne, end="")
    measurements = client.get_list_measurements()
    for measurement in measurements :
        if ligne == measurement['name'] :
            print("found, ", end="")
            result = client.query('select count(value) from "' + ligne + '";')
            try:
                print("count before: %d, " % result.raw['series'][0]['values'][0][1], end="")
            except Exception :
                print("N/A, ", end="")
            client.drop_measurement(ligne)
            result = client.query('select count(value) from "' + ligne + '";')
            try:
                count_after = result.raw['series'][0]['values'][0][1]
                print("count after: %d" % count_after, end="")
            except Exception :
                print("drop OK (not found)", end="")
file.close()