MySQL auto increments disappeared

Question

I have a MySQL database with 60 tables. Most tables have primary keys (expect pivot tables). All these primary keys had the AUTO INCREMENT attribute.

Then, overnight, somehow all the primary keys deleted this attribute, and the default value is 0.

I do not know what could cause this. Any suggestions?

Answer 1

Incorrect backup / restore is possible. I recently found out that mysqldump with the --skip-opt option will disable the auto-increment index --skip-opt