My mdl_logstore_standard_log.ibd file is 12 GB, for 57,500,000 records.
But i think you must know several things about the log table :
- information about deleted courses still exists in the table
- when resetting a course, it does not delete previous logs for this course!
Information is deletted only based on the loglifetime variable (mine is configured for 2 years / 730 days).
So, depending on the way you use your Moodle, and the number of years you used it, log table perhaps still stores a big number of totally unneeded information.
You can manually delete information about deleted courses and reseted course (before the start date) with appropriate queries if you want.