Re: coufused about ibtmp1

[eimmaa rose]

Hi Victor,

You’re right — in MySQL 8.4, ibtmp1 mainly serves as the temporary undo tablespace for user-defined temporary tables and other temporary operations that need undo logs.

To add a bit more detail:

The #innodb_temp/temp_*.ibt files correspond to the actual temporary tables created in the innodb_temp directory.

The ibtmp1 file stores undo information related to operations performed on those temporary tables (like INSERT, UPDATE, or DELETE).

Once the session or temporary table is dropped, both the undo space in ibtmp1 and the related temp_*.ibt file are released.

So yes, your observation about the modification times changing makes sense — it shows MySQL is writing both data and undo logs as expected.

Hope that clarifies things a bit!

— Eimmaa Rose