UI freezes/crashes when selecting or editing a cell with large data in Data tab

1 posts
homliangwu's profile image homliangwu posted 3 weeks ago in General Permalink

Summary

When viewing a table with large cell contents (e.g., long JSON, large TEXT/LONGTEXT or BLOB), clicking/selecting or attempting to edit an individual cell in the Data tab causes HeidiSQL to freeze permanently (Not Responding) and requires a force close.

Steps to Reproduce

  1. Connect to a database containing a table with large cell contents (e.g., text > a few MBs or huge single-line strings).
  2. Open the Data tab and locate the row with the large data.
  3. Click or double-click the cell containing the large value.

Expected Behavior

The UI should remain responsive. The application should either truncate the preview inline, load content asynchronously, or prompt before loading/rendering the entire large text into the editor component.

Actual Behavior

The entire HeidiSQL GUI freezes completely (Windows reports "Not Responding") and memory/CPU usage spikes, forcing the user to kill the process via Task Manager.

Environment

  • HeidiSQL Version: [e.g., 12.8.0.6900 / 64-bit] (Help -> About HeidiSQL)
  • OS: Windows 11 (x64)
  • Database Server / Version: [e.g., MySQL 8.0 / MariaDB 10.x]
  • Approximate Data Size / Column Type: [e.g., LONGTEXT / ~5MB JSON string]

Additional Context

  • The issue occurs when HeidiSQL attempts to load and render the raw string in the grid cell / text editor panel.

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