Regarding "[Warning] InnoDB: Cannot add field"

[Stephen Kwok]

Hi,

I'm looking into the following warnings. It is the same kind of warning while one is regarding a regular table and the other is a tmp table. Can someone please help me understand them?

My interruption is that the row size has exceeded the max and as the row format is dynamic, it should just store the column values off-page which is the expected behavior; therefore, the warning is more like an FYI.

[Warning] InnoDB: Cannot add field <column_a> in table <db_a>.`#sql-ib693-621870abc` because after adding it, the row size is 8144 which is greater than maximum allowed size (8126) for a record on index leaf page.

[Warning] InnoDB: Cannot add field <column_b> in table `db_a`.`table_b` because after adding it, the row size is 8128 which is greater than maximum allowed size (8126) for a record on index leaf page.

The database hosting on: AWS RDS
MySQL version: 5.7.33
innodb_default_row_format: Dynamic

Thanks very much.