Hi, I’d be grateful for a little help please.
I have a sensor which provides data every 5 seconds, and my goal is to have the previous 1 hour of data at 5 second precision, and older data downsampled to 10 minutes.
So far I’ve followed this example, by creating;
Retention Policies -
name duration shardGroupDuration replicaN default
---- -------- ------------------ -------- -------
one_hour 1h0m0s 1h0m0s 1 true
one_year 8736h0m0s 168h0m0s 1 false
and a Continuous Query -
CREATE CONTINUOUS QUERY "cq_5m" ON "emoncms" BEGIN
SELECT mean("grid") AS "grid",mean("solar") AS "solar", mean("divert") AS "divert", mean("usage") AS "usage"
INTO "one_year"."downsampled_iot"
FROM "iot" GROUP BY time(5m) END
The problem is that I was expecting (and hoping!!) that as soon as the 5 minute averaging had been done, and the results written to "one_year"."downsampled_iot"
, that the data used for those calculations would then be deleted from the measurement iot
, but instead, there is a considerable delay, and I have overlapping data in both measurements - somewhere between a 1hr & 2hr overlap.
My ultimate goal is to run a query to combine data from both iot
& one_year"."downsampled_iot
and display it in a single Grafana chart, so that I can see greater precision for the previous hour (for fault inspection).
EDIT - tried setting the one_hour
retention policy to 5 minutes, but get ERR: retention policy duration must be at least 1h0m0s
.