Empty resultset causes error on grafana

[brunoleite]

What happened:
When a query returns an empty resultset, Grafana shows an error on the panel and a javascript error on the web developer console.

What you expected to happen:
Empty panel with no errors or in case of multiple queries on the same panel, the query that does not return data should be ignored.

How to reproduce it (as minimally and precisely as possible):
Create a time series chart with the following query (more than one might be needed):

WITH
    binnedTimeseries AS (
      SELECT BIN(time, 10000ms) AS binnedTime, SUM(measure_value::double) as value
      FROM $__database.$__table 
      WHERE $__timeFilter 
        AND measure_name = 'any_metric_name'
      GROUP BY BIN(time, 10000ms)
      ORDER BY binnedTime
    ),
    interpolatedTimeseries AS (
      SELECT 
        INTERPOLATE_FILL(
          CREATE_TIME_SERIES(binnedTime, value),
          SEQUENCE(min(binnedTime), max(binnedTime), 10000ms),
          sqrt(-1)
        ) AS interpolatedValue
      FROM binnedTimeseries
    )
    SELECT *
    FROM interpolatedTimeseries

Running the query in a standalone client, it returns the following result:

Query Result:

{
  "QueryId": "#QueryId#",
  "Rows": [
    {
      "Data": [
        {
          "NullValue": true
        }
      ]
    }
  ],
  "ColumnInfo": [
    {
      "Name": "interpolatedValue",
      "Type": {
        "TimeSeriesMeasureValueColumnInfo": {
          "Type": {
            "ScalarType": "DOUBLE"
          }
        }
      }
    }
  ],
  "QueryStatus": {
    "ProgressPercentage": 100,
    "CumulativeBytesScanned": 0,
    "CumulativeBytesMetered": 10000000
  }
}

Screenshots:

Anything else we need to know?:

• Unrelated question: I added the external query with interpolation because I need to show gaps on the chart. This was the only way that I managed to have it working on grafana + time stream. I am not sure if I should open a feature request here or on grafana for this.
• There is a typo in the message 'colum':

  timestream-datasource/pkg/timestream/helper.go

  Line 51 in e623578

  dr.Error = fmt.Errorf("Expecting timeseries colum at: %d", timeseriesColumn.columnIdx)

Environment:
Grafana version: 8.5.2
Plugin version: 1.5.2
OS Grafana is installed on: Debian
User OS & Browser: Firefox
Others:

[sarahzinger]

I can recreate this as well. Going to move it to our backlog, I'm not entirely sure if it's ok for us to just remove the error check or if it's necessary, but we should at least fix the typo.

[kevinwcyu]

This was released in v2.0.0. Null value data points no longer trigger the error.