Angle brackets < > in field values are missing, and Superset slows after enabling RENDER COLUMNS IN HTML FORMAT

[SukiSeven]

I found two related issues in Superset when working with MySQL data:

1.Field values with angle brackets are missing

In MySQL the value is:
(HOFO,6hd, 6.0)
But in Superset it only shows:
(HOFO,6hd, 6.0)

This happens at row 144 — the and parts are missing there. The problem is inconsistent: some <...> fragments are preserved, others are hidden.
The text inside < > is missing (not all brackets are dropped, but some).
I have already enabled RENDER COLUMNS IN HTML FORMAT, but the issue still happens.
Expected: Superset should display the text exactly as stored in MySQL, including < >.

2.Performance issue after enabling HTML rendering
Previously, Superset did not have the RENDER COLUMNS IN HTML FORMAT option.
Our DevOps team added this feature by editing .tsx files and rebuilding the image.
After rebuilding, Superset became noticeably slower when rendering tables.
Why would enabling this option and rebuilding cause such performance degradation?

[dosubot[bot]]

Superset interprets angle brackets (< >) in field values as HTML tags, which can cause the text inside them to be hidden or truncated when HTML rendering is enabled. This is a known issue—disabling the "Render Columns in HTML Format" option in table settings will prevent Superset from treating angle brackets as HTML and display the full data as plain text instead. The same applies to SQL Lab, where you should disable the "Render HTML" option for complete data display [source].

Performance degradation after enabling HTML rendering is likely due to increased DOM complexity and React rendering overhead. Rendering raw HTML in many table cells forces the frontend to do extra parsing, escaping, and potentially unsafe rendering, which slows down UI updates—especially with large datasets. The DataTable component uses React hooks and memoization for optimization, but rendering HTML content in cells can bypass these optimizations and increase computation per cell, leading to slower table rendering [source].

If you want to display angle brackets as plain text and improve performance, it's best to keep HTML rendering disabled for your tables.

To reply, just mention @dosu.

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[SukiSeven]

Superset interprets angle brackets (< >) in field values as HTML tags, which can cause the text inside them to be hidden or truncated when HTML rendering is enabled. This is a known issue—disabling the "Render Columns in HTML Format" option in table settings will prevent Superset from treating angle brackets as HTML and display the full data as plain text instead. The same applies to SQL Lab, where you should disable the "Render HTML" option for complete data display [source].

Performance degradation after enabling HTML rendering is likely due to increased DOM complexity and React rendering overhead. Rendering raw HTML in many table cells forces the frontend to do extra parsing, escaping, and potentially unsafe rendering, which slows down UI updates—especially with large datasets. The DataTable component uses React hooks and memoization for optimization, but rendering HTML content in cells can bypass these optimizations and increase computation per cell, leading to slower table rendering [source].

If you want to display angle brackets as plain text and improve performance, it's best to keep HTML rendering disabled for your tables.

To reply, just mention @dosu.

How did I do? Good | Irrelevant | Incorrect | Verbose | Hallucination | Report 🐛 | Other    

thanks for the explanation! Could you let me know where exactly the "Render HTML" option is located in Superset (for both Table chart and SQL Lab)? I wasn’t able to find it.
@dosu.

[dosubot[bot]]

Here’s where you can find the "Render HTML" options in Superset:

Table Chart Visualization:
Open your Table chart, then go to the chart settings panel (usually on the left or right side of the visualization editor). Look for the option labeled "Render Columns in HTML Format" and uncheck it to disable HTML rendering. This will ensure angle brackets and other HTML-like content are displayed as plain text in your table [source].

SQL Lab:
In SQL Lab, the "Render HTML" toggle is in the SQL Editor toolbar. Click the ellipsis button (three dots) on the right side of the toolbar to open the dropdown menu. You’ll see a menu item labeled "Render HTML" with a switch to enable or disable it. Turning this off will display your query results as plain text, preserving angle brackets and preventing HTML interpretation [source].

No recent changes or documentation updates affect these locations or labels. Let me know if you need a screenshot or more details!

To reply, just mention @dosu.

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