Duplicate values stored in database

Store
1

We are in the final stage of going live with InfluxDB as our time series database but at the last moment, I ran into one critical issue about duplicate points being stored for single timestamp-tag pair.

> SELECT "time", "2001", "SensorId" FROM dbname.autogen.Reading WHERE "SensorId" = '17186' AND time >= 1557953095198000000 and time <= 1557953103853000000 GROUP BY "SensorId";
name: Reading
tags: SensorId=17186
time                2001              SensorId
----                ----              --------
1557953099000000000 330638950.4       17186
1557953099000000000 330967451.0651455 17186

Influx Version: 1.7.4

Actual Behaviour
Duplicate field values stored for one tag and timestamp pair.

Expected Behaviour
The value should have override and only one value should have present.

2

a) Do you get the same result without the “group by SensorId”?

b) What are you using for “precision”?

Antony.

3

Yep same result without group by

> SELECT "time", "2001", "SensorId" FROM dbname.autogen.Reading WHERE "SensorId" = '17186' AND time >= 1557953095198000000 and time <= 1557953103853000000;
name: Reading
time                2001              SensorId
----                ----              --------
1557953099000000000 330638950.4       17186
1557953099000000000 330967451.0651455 17186

And it’s using nano second precision.

4

Hi @HardikSondagar ,

I am sure 2001 is a field but could you double check with show tag keys from Reading ?
Do you overwrite many times ?

best regards ,

5

Yes, 2001 is field, I’ve verified this by field keys

> SHOW FIELD KEYS ON "dbname" FROM "Reading"
name: Reading
fieldKey fieldType
-------- ---------
2001     float
2022     float
2030     float
2118     float
2119     float

Yes I’m overwriting data for 2-3 times. As our data doesn’t comes realtime always, sometimes because of network issue, we receive data after 2-3 days, so need to re-downsample every day for last 2-3 days.

6

Could be an unknown bug ,
are you using tsi1 indexes ?
Can you reproduce the situation on a new database or can you rebuild the indexes on a copy of your database ?

7

It’s kinda scary situation, I’m about to go live with influxdb in production but this is a serious bug.

Yes, I’m using tsi1 indexes and will try to reproduce the same on new database.