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DocumentationTDSQL-C for MySQLKernel FeaturesInspection and Repair of Kernel IssuesInstant change column redo Flaw in Buffer Calculation Causes crash

Instant change column redo Flaw in Buffer Calculation Causes crash

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Last updated: 2025-12-08 15:56:17

Problem

A calculation defect in the buffer for instant change column redo causes a crash.

Scenario that Triggers the Issue

The calculation of log index size must account for changes in column order and record the size of index information in the redo log, as these columns were not previously included. A crash occurs when an UPDATE operation is executed immediately after ALTER TABLE to modify column order, due to miscalculation of redo log space allocation.

Kernel Version Related to the Issue

TXSQL 8.0 versions prior to 3.1.15.002.

Fixed Kernel Version

TXSQL 8.0 3.1.16.003.

Check Method

You can refer to the following command to scan 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 Method

1. Upgrade the kernel version to TXSQL 8.0 3.1.16.003. For the procedure, see Upgrading the kernel minor version.
2. After the kernel version is upgraded, rebuild and repair corrupted tables using alter table xx engine = innodb;. To avoid business impact caused by table locking, it is recommended to perform repairs during off-peak hours using tools such as pt-osc.

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