The problem is not in the temporary table itself but in the DELETE query which is executed on the target table and that temporary table. It seems that MySQL doesn’t optimize it good enough and deletes only 15-20 rows per second.
As a workaround you can try to:
- Export the keys which you are trying to match to a temporary table with the “Export to DB” action.
- Run a custom DELETE SQL query which will delete required rows. Custom SQL can be executed with the “Custom command” mode of the “Database command” action.
Custom DELETE SQL query may use:
- JOIN on a target and a temporary table and WHERE condition which will filter rows which have not matches in the temporary table
or - WHERE with NOT IN condition and a subselect on the temporary table.