MySQL Error 3178: Online Index on Virtual Column

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Description

This error signifies an attempt to add an index to a VIRTUAL column using an ALTER TABLE statement that tries to perform the operation 'online'. MySQL currently does not support adding indexes to virtual columns with certain online DDL algorithms, requiring a different approach.

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Error Message

ADD COLUMN col...VIRTUAL, ADD INDEX(col)

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Known Causes

3 known causes

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Unsupported Online DDL Algorithm

Attempting to add an index to a virtual column using an ALTER TABLE statement with an ALGORITHM (e.g., INPLACE or INSTANT) that is not supported for this specific operation.

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Implicit Online Operation

Relying on MySQL's default DDL algorithm which attempts an online operation, but fails when adding an index to a virtual column.

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MySQL Version Limitations

Using a MySQL version that has specific limitations or does not fully support online DDL for adding indexes to virtual columns.

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Solutions

Coming Soon

Detailed step-by-step solutions for this error are being prepared. In the meantime, try these general troubleshooting tips:

General Troubleshooting Tips

Check the error message carefully for specific details
Review recent changes that might have caused the error
Search for the exact error code in the official documentation
Check log files for additional context
Try restarting the application or service

Find Help

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Related Errors

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