zMODid is a special calculation field that is needed by the complex controls such as GanttChart and DayCal to detect when records have been modified by another user. You need to set it up as a numeric calc field in the related table. It is best for Reactor if it is an unstored calculation, defined as:
Get ( RecordModificationCount )
If you want to make it a stored calc, use one of the following:
and for DayCal:
Reactor uses a polling technique to check for record changes on the database. Every 4 seconds (by default) the Reactor control will send a request back to the database to retrieve the last modification count. It will then compare the modification count with the last modification we received from the database, and update any records if necessary.
Because the control is constantly checking records, if your database is running over a WAN, or has a large number of records, this may impact performance.
In most cases, you can solve the issue by indexing the required fields: any fields that are used in your relationship — along with the start date, start time fields, and duration field (in the case of the calendars, and charts) will have an impact.