Linux/TimescaleDB

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Revision as of 13:36, 13 October 2024 by Marcluer (talk | contribs) (→‎Time bucket)
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Setup

CREATE TABLE sensor_data (
        time TIMESTAMPTZ NOT NULL,
        topic TEXT,
        value DOUBLE PRECISION
);
SELECT create_hypertable('sensor_data', 'time');

Insert data via Node-RED

INSERT INTO sensor_data (time, topic, value) VALUES (
    now(),
    '{{{ msg.topic }}}',
    '{{{ msg.payload }}}'
);

Get table size

SELECT hypertable_size('sensor_data');

Time buckets

SELECT time_bucket('15 minute', time) as fifteen_min,
  avg(value) AS avg_value
FROM "sensor_data"
WHERE "topic" = 'home/plug-c86044-fridge/sensor/power'
GROUP by fifteen_min
ORDER by fifteen_min DESC
LIMIT 50

Counters

SELECT time_bucket('1 hour', time) as bucket,
 first(time,time) as period_begin,
 last(time,time) as period_end,
 MAX(counter) - MIN(counter) as total_consumption
FROM 
GROUP BY 1;

first() + last ()

Continuous aggregates

Links