Error
Error Code:
4093
MySQL Error 4093: Row Size Exceeds Limit
Description
This error occurs when attempting to add a new column to a table using the ALGORITHM=INSTANT option in MySQL. It signifies that the potential maximum row size, after adding the new column, would exceed the permissible limit for the storage engine (typically InnoDB), a condition that ALGORITHM=INSTANT cannot handle.
Error Message
Column can't be added with ALGORITHM=INSTANT as after this max possible row size crosses max permissible row size. Try ALGORITHM=INPLACE/COPY.
Known Causes
3 known causesAttempting Instant Add with Large Row Size
The ALGORITHM=INSTANT operation is chosen for adding a column, but the combined size of existing columns and the new column definition exceeds the maximum row size limit for this algorithm.
Existing Table Near Max Row Size
The table already contains many or large columns, bringing its current or potential row size close to the InnoDB maximum, making any instant schema modification problematic.
New Column Increases Row Size Significantly
The new column being added, especially if it's a large VARCHAR, TEXT, or BLOB type, significantly increases the potential row size beyond the allowed limit for an instant operation.
Solutions
Coming SoonDetailed 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