loop inert and delete, the Active(file) of memory will Abnormal increase

[SimonsSoft]

Test case:

1. Insert 1000 records, every record have 8192 Byte blob data;
2. sleep 30;
3. get and delete record one by one.

issue: the database file only 8.4 M size，But memory free decrease ~600M. before: after:

Thank You!