New time series charts show all data missing if one part of "contribution" is missing

[serenajiang]

When you create a time series viz with a groupby and contribution Total, if at least one of the categories is missing a value for the date, no data points for that date are shown.

This is sort of reasonable - technically, the data could be missing for the missing category, so it is not clear how to calculate contribution. However, in most cases, the missing data point corresponds to the value 0, and removing all the other data points is very confusing. In older charts (ex. line chart), contribution assumes 0 if data is missing, so we should provide some way to "fill" 0 for feature parity.

I think there are two ways

• Assume 0 whenever data is missing (similar to legacy line chart)
• Have users use resample to fill missing values with 0. This is not possible yet because resample doesn't work if there's a group by - the error message is: cannot reindex from a duplicate axis and occurs here

How to reproduce the bug

1. Go to SQL Lab
2. Run query:

SELECT DATE('2021-09-01') AS ds, 'hi' AS x
UNION ALL SELECT DATE('2021-09-02') AS ds, 'hi' AS x
UNION ALL SELECT DATE('2021-09-01') AS ds, 'whoa' AS x

3. -> explore chart
4. Use time series bar chart v2 viz
5. Group by x, metric count, contribution total
6. Note the missing data point for (2021-09-02, hi)

Expected results

Two bars should be shown for 09-01, one bar should be shown for 09-02

Actual results

No bars are shown for 09-02, even though there is a data point

Environment

(please complete the following information):

• browser type and version: chrome
• superset version: up to date with master as of 2021-10-01
• python version: 3.8

Checklist

Make sure to follow these steps before submitting your issue - thank you!

• I have checked the superset logs for python stacktraces and included it here as text if there are any.
• I have reproduced the issue with at least the latest released version of superset.
• I have checked the issue tracker for the same issue and I haven't found one similar.

Additional context

This is somewhat related to this issue: #15036

[serenajiang]

@zhaoyongjie Any suggestions on how to proceed?

[serenajiang]

fyi @junlincc this was one of the asks from our users when giving echarts feedback

[zhaoyongjie]

@zhaoyongjie Any suggestions on how to proceed?

I will follow up resample operator to support groupby.

[etr2460]

@zhaoyongjie did you get a chance to work on this?

[zhaoyongjie]

@zhaoyongjie did you get a chance to work on this?

Got it. I will ship it after monorepo project.

[serenajiang]

@zhaoyongjie Any updates on this?