• accesslog,
• all tables starting with 'cache' and
• watchdog.

The emptying out process is not absolutely necessary but you will note that the table 'accesslog' holding 24,000 odd records accounts for nearly half of all records in the database. Simply click the 'Empty' button alongside the relevant table name. As is usual with this type of operation you must confirm that you do in fact do want to empty the table. The term used is 'truncate' which means empty the table.

Note that we are not deleting the table, merely emptying the records.

Repeat this for all the tables to be emptied as listed above (also highlighted in the image above).