PDMS/E3D Help:

PDMS sessions enable a history of changes to the database to be recorded. When a new session is made, the changed data is appended to the end of the database file. Appending updated data to files will increase the disk space required. If the history information is not required, and to save disk space, you can compact a database by merging sessions.

According to above phrases from PDMS/E3D Help, it is required to merge sessions periodically by Admin. This prevent to increase the disk space required for project DB's.

By this tool, after a confirmation, iDEES merge all sessions in all project databases in the active profile project.

This tool will work like the following tool in the PDMS/E3D itself:

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