CSV format does not retain timezone information for timestamp type columns in query result

[bimalkant-lauhny]

Issue Summary

I use Postgres for storing timestamp with timezone for some columns (timestamptz type). When I download the query results in CSV, the timezone information is missing. I can confirm that timezone info in CSV was there in Redash v7. It is also there if I download the results in Excel format for Redash v8.

Steps to Reproduce

1. Run some query which produces timestamp in results. For example, in Postgres, one can run this query:

SELECT NOW();

2. Download the result in CSV format. The timestamp value will not have timezone information. For example, my CSV contents after running the query in Step 1 were as below:

now
2020-04-21 20:49

Excel format file had the contents as below:

now
2020-04-21T20:49:00.224+07:00

Why do you consider this to be a bug?

It seems like the CSV just stores local timezone and the precision is also less (there is no seconds info). This can be very confusing if someone is accessing Query results in other timezone, or comparing query results of multiple timezones.

What did you expect to happen instead?

Just like in Excel format, the CSV format should also have timezone information for timestamp columns.

Technical details:

• Redash Version: 8.0.2
• Browser/OS: Chrome/Ubuntu 18.04
• How did you install Redash:

[susodapop]

I reproduced this on our preview instance. It affects the latest alpha build of V9 as well.

[tim5go]

@susodapop
From here:

redash/redash/serializers/query_result.py

Lines 92 to 99 in 100c7be

	for row in query_data["rows"]:
	for col_name, converter in special_columns.items():
	if col_name in row:
	row[col_name] = converter(row[col_name])
	writer.writerow(row)
	return s.getvalue()

We see that the query result value is formatted by the converter.

If we trace back several steps, we will find that the time format is controlled by the environment variable.

redash/redash/settings/organization.py

Line 23 in 72dc157

TIME_FORMAT = os.environ.get("REDASH_TIME_FORMAT", "HH:mm")

I believe you can overwrite the format whatever you want, and personally I won't consider this behaviour as a bug.