DASHBOARD_JSON_MAX_LENGTH ignored in Superset 6.0.0 – Dashboard save still fails with “Your dashboard is too large”

[parag2131]

Bug description

Superset Version
Superset Version: 6.0.0
OS: Amazon Linux (EC2)

Issue Description

We are getting the following error while saving a dashboard:
"Your dashboard is too large. Please reduce its size before saving it."
The dashboard contains multiple KPI Big Number charts and tabs.
It exceeds the default 65535 JSON size limit.

We updated the backend config:
DASHBOARD_JSON_MAX_LENGTH = 1000000

The container was restarted after the change.
However, the dashboard save still fails with the same error.

Actual Behavior

Even after increasing the limit to 1,000,000 and restarting the container, Superset still throws:
"Your dashboard is too large. Please reduce its size before saving it."

Question

Is there another limit introduced in Superset 6.0.0?
Is this validation happening on frontend?
Is there a new config key replacing DASHBOARD_JSON_MAX_LENGTH?
Is there a database-level column limit (e.g., TEXT vs MEDIUMTEXT equivalent)?

If there is any additional config required in 6.0.0, please advise.

Screenshots/recordings

No response

Superset version

master / latest-dev

Python version

3.9

Node version

16

Browser

Chrome

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.

[dosubot]

In Superset 6.0.0, the dashboard JSON size limit is controlled by the config key SUPERSET_DASHBOARD_POSITION_DATA_LIMIT, not DASHBOARD_JSON_MAX_LENGTH—the latter is no longer used. The default limit is 65535 characters, which matches the error threshold you're seeing. To increase the limit, set SUPERSET_DASHBOARD_POSITION_DATA_LIMIT = 1000000 in your superset_config.py and restart all Superset services (web server, worker, etc). This limit is enforced on both backend and frontend, so the UI will also block saves above this threshold source.

Superset stores dashboard layout JSON in the position_json column, which uses a custom MediumText type (MEDIUMTEXT for MySQL), supporting much larger storage than standard TEXT (up to 16MB in MySQL), so the database is unlikely to be the limiting factor unless your dashboard is extremely large source.

If the error persists after updating the config and restarting, double-check that your config file is being loaded correctly, that there are no containerization or path issues, and clear any frontend caches. For very large dashboards, consider splitting them to avoid performance issues.

Let me know if you need help verifying your config or troubleshooting further.

To reply, just mention @dosu.

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[hainenber]

Dosu's response is correct. Can you try to modify the newly config SUPERSET_DASHBOARD_POSITION_DATA_LIMIT to see if it fixes out your issue?