Global Change Management

AVEVA Global User Guide

Hub Administration : Remote Operations : Global Change Management

Selecting Remote > Global Change Management > Global Merge Changes displays the Global Merge Changes window.

Each time a user does a SAVEWORK or module switch, a new session is created for that user for each modified database. To save disk space, the Global Merge Changes window can be used to merge database sessions for a remote location. This will merge the database at its primary location first, then updates the database at all available secondary locations.

Use The Databases of option to select the remote location for which the database sessions are to be merged.

Merge the changes to the System databases, or to a Single Project database. If Single Project database is chosen, select a database from the Available databases list. The user can merge All Changes, Changes Up to or Changes After a given time, date or session number.

The Rebuild list option is used to update the list of databases. For example, if a new database has been created while the window is displayed, the list will not be updated until the window is closed and re-displayed, or the Rebuild list option is clicked.

To schedule a time for the merge to take place, click Timed Merge to display the following window.

Enter a time in the format HH:MM:SS and a date in the format DD MMM YYYY.

Click Apply to store the input values.

Click Cancel to close the window.

After specifying the sessions to merge, click Apply to merge changes. Some session data will be deleted. The sessions remaining are those that you have either kept deliberately, or stamped sessions, as these are considered permanent and are not merged.

Note:

Database Management
It is important for a System Administrator to consider merging (compressing) databases. Each organisation will have different working practices but may wish to consider merging databases on a daily basis.

Each time a user does a SAVEWORK, a new dB session is created, so for any working day there may be hundreds of sessions added to a multiwrite database. These can be merged into one session for each day. This would keep the number of sessions per year to a manageable 300-400 sessions. Older sessions could be further compressed to weekly or even monthly increments, whereas newer data compression could be delayed by a day or merged into hourly increments, prior to the daily merge, to allowing more accurate backtracking if necessary.

The above information is given as a guideline for consideration but each organisation needs to decide on there own course of action.

Database Stamps

Database sessions included within a Stamp are considered permanent and are not removed when a MERGE CHANGES command is given.