apache
[Bug] Query error, An error occured within the plugin
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- [X] I searched in the issues and found nothing similar.
Version
IoTDB 1.2.2 Standalone IoTDB Grafana Plugin 1.0 (Grafana interface) Grafana 10.2.2
Describe the bug and provide the minimal reproduce step
Problem Description
When executing a SELECT LAST_VALUE(*) align by device query using grafana IoTDB plugin the query return an error. While the IoTDB CLI returns the expected and accurate results
Grafana Explore Query
also tried without the * on the SELECT Statement:
IoTDB Cli
What did you expect to see?
Expected Behavior
The same table that IoTDB Cli return using the same syntax:
What did you see instead?
Actual Behavior
Using this syntax on Grafana with the IoTDB plugin return "Query error, An error occured within the plugin"
Anything else?
Also tried using DISTINCT Statment but nothing changed
The blurried part of the path are just for obscure sensitive data.
Are you willing to submit a PR?
- [ ] I'm willing to submit a PR!
Hi, Grafana Plugin doesn't support aggregate with align by device due to the ResultSet missing time column. It is not a bug.
@HTHou I've come across some queries that function well using the "align by device" method with both the LAST_VALUE and DISTINCT IoTDB functions.
DISTINCT FUNCTION
and it also returns a timestamp
LAST_VALUE FUNCTION
I suspect that Grafana appends a dummy timestamp (1970-01-01 01:00:00) to compensate for the fact that IoTDB doesn't always return a timestamp. However, as shown before some times it returns an error which is really difficult to debug without a proper message. In my opinion, this inconsistency is a bug since the functionality should ideally work consistently, either every time or never. It might be worth investigating further to ensure reliable behavior.