Crash Caused by Instant ADD COLUMN of a Column with the Same Name after Instant DROP
Last updated:2025-12-24 16:09:19
Crash Caused by Instant ADD COLUMN of a Column with the Same Name after Instant DROP
Last updated: 2025-12-24 16:09:19
Issue
Performing an instant ADD COLUMN operation on a column with the same name followed by an instant DROP operation causes a crash.
Issue Triggering Scenarios
After an instant DROP operation is performed, the column is not actually deleted but is renamed and becomes a hidden column. If an instant ADD COLUMN operation is then performed to add a column with the same name as the hidden column, it can lead to metadata inconsistency, resulting in a crash.
Affected Kernel Versions
MySQL 8.0 20221221 and earlier versions.
Fixed Kernel Version
MySQL 8.0 20241005.
Check Methods
You can refer to the following commands to check for tables with potential risks.
select replace(name, '/', '.') as 'table_schema.table_name' from information_schema.innodb_tables where TOTAL_ROW_VERSIONS!=0 or INSTANT_COLS!=0;
Fixing Methods
1. Upgrade the kernel version to MySQL 8.0 20241005. For the operation method, see Upgrading the Kernel Minor Version.
2. After a kernel version upgrade, rebuild and repair the corrupted tables. You can use the method
alter table xx engine = innodb; for repair. To avoid business impact caused by table locking, it is recommended to perform the repair during off-peak hours using tools such as pt-osc.Was this page helpful?
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