Superset leaks open db connections

[martimors]

Bug description

I have performed some load testing on our superset instance, and to my surprise, the limiting factor is the number of open database connections. In our case, the database is a rather beefy postgresql instance hosted in Azure.

I made the load test bombard the following endpoints using Locust:

• Log in (once per user)
• List datasets, api/v1/datasets (weight 100)
• Create and delete a chart, api/v1/chart (weight 10)
• Get a data sample for a chart, api/v1/chart/data (weight 1, this hits DataBricks)

After some time, the console gets spammed with errors from sqlalchemy that the connection pool is full.

Somewhere in the app, connections are opened and not being closed, and this severely hampers performance.

Screenshots/recordings

No response

Superset version

4.1.1

Python version

I don't know

Node version

I don't know

Browser

Not applicable

Additional context

No response

Checklist

• I have searched Superset docs and Slack and didn't find a solution to my problem.
• I have searched the GitHub issue tracker and didn't find a similar bug report.
• I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.