Same query different results

TimescaleDB and PostgreSQL
1

I am charting my data on grafana. I noticed when I do few refreshes the data is different everytime eventhough I have the same time range. I don’t think its a grafana problem but timescaledb.

My query looks like this

select "time" as "time",
pend from bar WHERE "time" BETWEEN '2024-07-29 1:00Z' AND '2024-07-29 04:00Z' and ele='j1' ORDER BY 1

I run the query 10 times and put it in 10 files. All 10 files have the same number of rows. However, if I do a diff I see a subtle differences.

For example

diff 1.out 4.out
...
3251a3253.3254
< 2024-07-29 3:15:20 | 
...

If I do it again completely different again. Am I doing my query correctly?

2

Not sure how your data looks like but if time is not uniquely identifying rows you might have to include additional columns in the order by clause to get reproducible results.