Question: Encountered "Failed to save slice" error when saving chart to dashboard

[sukisevensuki-jpg]

Hi community,

I am using [Software Name, e.g., Apache Superset] version [4.0.1].
I encountered an error message "Failed to save slice" when trying to save a chart.

Context:

• I was trying to save a chart .
• I attempted to overwrite an existing slice or add it to the dashboard.
• The popup error says: "Failed to save slice".

Screenshots:

Has anyone experienced this before?

Any advice would be appreciated! Thanks.

[dosubot[bot]]

This is a known issue with several potential causes. Here are the most common ones and their solutions:

1. Invalid color fields in chart metadata
This is frequently the culprit. Try editing the chart, going to the "Advanced" section, and removing or clearing the map_label_colors or shared_label_colors fields (related fix).

2. Frontend/backend version mismatch
If you're running Superset in a distributed setup, ensure both frontend and backend are on the exact same version. Even minor mismatches can cause schema validation errors.

3. NULL query_context (common after imports)
If you imported this dashboard via a zip file, charts may have NULL query_context. Re-opening and re-saving each chart in the Explore view rebuilds the query context.

4. Permission issues
Verify you have "can write on dashboard" permission for the target dashboard.

Troubleshooting tip: Check your backend logs for the full error message/stack trace—it will give you more specific details about what's failing.

Also worth noting: several chart-saving bugs were fixed in versions after 4.0.1 (PR #36441, PR #36402), so upgrading may help if the above doesn't resolve it.

To reply, just mention @dosu.

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[dosubot[bot]]

Based on your role configuration, the Gamma role does include can write on Chart by default, so that's not the issue. However, there are a few things to verify:

Most likely cause: Datasource access mismatch

Even with can write on Chart, Gamma users are restricted to datasources they've been explicitly granted access to. Make sure the WAREHOUSE_RW role includes datasource_access on the exact dataset the chart is using—not just the database or table, but the specific Superset dataset object.

Other permissions to check:

1. Chart ownership – If the user is trying to overwrite someone else's chart, they won't have permission unless they're listed as an owner of that chart
2. Dashboard ownership – If adding to a dashboard, the user must be an owner of that dashboard
3. can read on Dataset and can read on Database – These are sometimes needed alongside datasource_access

Quick test: Have the user try saving the chart as a new chart (not overwriting) without adding it to any dashboard. If that works, the issue is likely ownership-related. If it still fails, it's almost certainly a datasource access issue.

Could you check the backend logs for the full error message? It usually specifies exactly which permission is missing.

To reply, just mention @dosu.

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[sukisevensuki-jpg]

Hi @dosu,

Current Status:

1. ✅ Save as New Chart: Works perfectly. The user can create and save new charts without issues.
2. ❌ Save (Overwrite/Update): Fails with "Failed to save slice" when trying to update an existing chart.
3. 👤 Ownership: I verified that the user IS the owner of the chart they are trying to update.
4. 🔧 Permissions Added: I explicitly added can read on Dataset and can read on Database to their roles (Gamma + sql_lab + WAREHOUSE_RW), but the overwrite issue persists.

[dosubot[bot]]

Thanks for the detailed update! Since creating new charts works but overwriting fails, there are a couple of specific things to check:

1. Missing can explore permissions

For chart updates specifically, the user needs can explore on Superset and can explore json on Superset in addition to the read/write permissions. These are often overlooked but required for the save/overwrite operation to succeed.

2. NULL query_context issue

If the chart was originally created or modified via API (or imported), it may have a NULL query_context. Charts in this state can fail on update. The fix is to:

1. Open the chart in Explore view
2. Make a trivial change (toggle something)
3. Save it once to regenerate the query_context
4. Then normal updates should work

Recommended next steps:

1. Add can explore on Superset and can explore json on Superset to one of the user's roles
2. Check the backend logs during the failed save—it will show the exact permission or validation that's failing
3. If logs mention query_context, try the manual resave workaround above

Can you share what shows up in the backend logs when the save fails? That will tell us exactly what's blocking it.

To reply, just mention @dosu.

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[sukisevensuki-jpg]

DB engine Error: "can not access the query" - Missing permission to execute SELECT query in SQL Lab

@dosu

[dosubot[bot]]

The "can not access the query" error in SQL Lab can be caused by a few different things. Here are the most common causes for Superset 4.0.1:

1. Cross-database query syntax (most likely in 4.0.1)

If you're using fully qualified table names like SELECT * FROM database_name.schema.table, this is a known issue introduced in 4.0.1. Superset now interprets the database prefix as a "catalog" and requires all_database_access or all_datasource_access permissions.

Workaround: Try removing the database prefix and using just schema.table in your query, or grant all_database_access to the user's role.

2. Jinja templating issue

If your query uses Jinja functions like {{ filter_values() }}, there's a known bug where permission checks fail because the Jinja context isn't properly initialized. This was fixed in PR #33568—check if your version includes that fix.

3. Missing SQL Lab permissions

Ensure the user's roles include these permissions on TableSchemaView:

• can post on TableSchemaView
• can delete on TableSchemaView
• can expand on TableSchemaView

Could you share the exact SQL query that's failing? That will help narrow down which issue you're hitting.

To reply, just mention @dosu.

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[fowlerp397-tech]

Thanks for the detailed update! Since creating new charts works out just fine

…

On Fri, Mar 13, 2026, 7:34 AM dosubot[bot] ***@***.***> wrote: Thanks for the detailed update! Since creating new charts works but overwriting fails, there are a couple of specific things to check: *1. Missing can explore permissions* For chart updates specifically, the user needs can explore on Superset and can explore json on Superset <#36088> in addition to the read/write permissions. These are often overlooked but required for the save/overwrite operation to succeed. *2. NULL query_context issue* If the chart was originally created or modified via API (or imported), it may have a NULL query_context <#31872 (comment)>. Charts in this state can fail on update. The fix is to: 1. Open the chart in Explore view 2. Make a trivial change (toggle something) 3. Save it once to regenerate the query_context 4. Then normal updates should work *Recommended next steps:* 1. Add can explore on Superset and can explore json on Superset to one of the user's roles 2. Check the backend logs during the failed save—it will show the exact permission or validation that's failing 3. If logs mention query_context, try the manual resave workaround above Can you share what shows up in the backend logs when the save fails? That will tell us exactly what's blocking it. *To reply, just mention @dosu <https://go.dosu.dev/dosubot?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=brand-link>.* ------------------------------ How did I do? Good <https://app.dosu.dev/response-feedback/028c1241-fca1-4b7a-a900-a2fab0b3a742?feedback_type=great_response&utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-great_response> | Irrelevant <https://app.dosu.dev/response-feedback/028c1241-fca1-4b7a-a900-a2fab0b3a742?feedback_type=irrelevant_answer&utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-irrelevant_answer> | Incorrect <https://app.dosu.dev/response-feedback/028c1241-fca1-4b7a-a900-a2fab0b3a742?feedback_type=incorrect_sources&utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-incorrect_sources> | Verbose <https://app.dosu.dev/response-feedback/028c1241-fca1-4b7a-a900-a2fab0b3a742?feedback_type=too_verbose&utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-too_verbose> | Hallucination <https://app.dosu.dev/response-feedback/028c1241-fca1-4b7a-a900-a2fab0b3a742?feedback_type=hallucination&utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-hallucination> | Report 🐛 <https://app.dosu.dev/response-feedback/028c1241-fca1-4b7a-a900-a2fab0b3a742?feedback_type=bug_report&utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-bug_report> | Other <https://app.dosu.dev/response-feedback/028c1241-fca1-4b7a-a900-a2fab0b3a742?feedback_type=other&utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=feedback-other> [image: Chat with Dosu] <https://app.dosu.dev/a28d3c7e-a9d3-459e-9fb6-3a6f9ff4f357/ask?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=chat-badge> [image: Open in Cursor] <https://cursor.com/link/prompt?text=Thanks%20for%20the%20detailed%20update%21%20Since%20creating%20new%20charts%20works%20but%20overwriting%20fails%2C%20there%20are%20a%20couple%20of%20specific%20things%20to%20check%3A%0A%0A%2A%2A1.%20Missing%20%60can%20explore%60%20permissions%2A%2A%0A%0AFor%20chart%20updates%20specifically%2C%20the%20user%20needs%20%5B%60can%20explore%20on%20Superset%60%20and%20%60can%20explore%20json%20on%20Superset%60%5D%28https%3A//github.com/apache/superset/discussions/36088%29%20in%20addition%20to%20the%20read/write%20permissions.%20These%20are%20often%20overlooked%20but%20required%20for%20the%20save/overwrite%20operation%20to%20succeed.%0A%0A%2A%2A2.%20NULL%20query_context%20issue%2A%2A%0A%0AIf%20the%20chart%20was%20originally%20created%20or%20modified%20via%20API%20%28or%20imported%29%2C%20it%20may%20have%20a%20%5BNULL%20%60query_context%60%5D%28https%3A//github.com/apache/superset/issues/31872%23issuecomment-2592899285%29.%20Charts%20in%20this%20state%20can%20fail%20on%20update.%20The%20fix%20is%20to%3A%0A1.%20Open%20the%20chart%20in%20Explore%20view%0A2.%20Make%20a%20trivial%20change%20%28toggle%20something%29%0A3.%20Save%20it%20once%20to%20regenerate%20the%20query_context%0A4.%20Then%20normal%20updates%20should%20work%0A%0A%2A%2ARecommended%20next%20steps%3A%2A%2A%0A%0A1.%20Add%20%60can%20explore%20on%20Superset%60%20and%20%60can%20explore%20json%20on%20Superset%60%20to%20one%20of%20the%20user%27s%20roles%0A2.%20Check%20the%20backend%20logs%20during%20the%20failed%20save%E2%80%94it%20will%20show%20the%20exact%20permission%20or%20validation%20that%27s%20failing%0A3.%20If%20logs%20mention%20%60query_context%60%2C%20try%20the%20manual%20resave%20workaround%20above%0A%0ACan%20you%20share%20what%20shows%20up%20in%20the%20backend%20logs%20when%20the%20save%20fails%3F%20That%20will%20tell%20us%20exactly%20what%27s%20blocking%20it.> [image: Join Discord] <https://go.dosu.dev/discord-bot?utm_source=github&utm_medium=bot-comment&utm_campaign=github-assistant&utm_content=join-discord> [image: Share on X] <https://twitter.com/intent/tweet?text=%40dosu_ai%20helped%20me%20solve%20this%20issue!&url=https%3A//github.com/apache/superset/discussions/38618> — Reply to this email directly, view it on GitHub <#38618 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B72HASJD4JDDAIJDVKJKWBD4QO2XXAVCNFSM6AAAAACWQTMDHOVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTMMJRGE4DOMI> . 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