Hello, why delete from ... doesnt modify size of odb? Even in in embedded mode, and in server mode i use recovery, not recording mode.
odb file size doesn't shrink
When objects are deleted from the database their space is marked as unused and becomes available for future objects. The size of the database is not reduced, as it usually better, considering performance, to keep the free space for future extension.
ObjectDB - Fast Object Database for Java (JPA/JDO)