Q&As about replication purge intervals and cutoff dates
What information is available about Notes client replication cut-off dates and purge intervals?
In the following questions and answers (Q&As), the following terms are used:
Purge Interval = 1/3 of the value found in the "Remove Documents Not Modified in the Last n Days" field (found in the Space Savers panel of the Replication Settings dialog box). By default, the Purge Interval is 1/3 of 90 days, or 30 days.
Cutoff Date (Purge Date) = the value in the "Only Replicate Incoming Documents Saved or Modified After" field (found in the Other panel of the Replication Settings dialog box).
Q: What is the Purge Interval? How does it relate to replication?
A: The Purge Interval is the number of days that stubs of deleted documents remain in the database before being permanently and completely removed. Every time a database is opened, the purge function checks the Purge Interval to determine whether or not to activate a purge. The purge function keeps track of when the database was created and of the date of the last purge.
Every time a database is opened, the purge function checks to see how long it has been since it was last run. If it has not been run for at least 1/3 of the Purge Interval, it activates and purges all deletion stubs that are older than the Purge Interval.
For example, if you created a database on day 1 whose purge threshold was set at 90, on day 30 the purge function would check to see if there were any deletion stubs older than 90 days. If there were, it would purge them. It would next check on day 60, then on day 90, then on day 120, etc. The first time that the purge could actually happen would be on day 120 (on day 90 there could not be any deletion stubs older than 90 days, only equal to 90 days). It would then purge any deletion stubs that were older than day 30 (120-90=30).
Q: How is the Purge Interval calculated?
A: The Purge Interval is 1/3 of the days in the "Remove Documents Not Modified in the Last n Days" field (30, by default).
Q: What criteria is used to calculate the date placed in the Cutoff Date field and why is a value in this field returned once it has been deleted?
A: The Cutoff Date is calculated based on the Purge Interval; this is true whether or not the "Remove Documents Not Modified in the Last n Days" box is checked.
When the Cutoff Date is deleted, it repopulates itself based on the value of the "Removed Documents Not Modified..." field. The Cutoff Date is set to n days ago. So, by default, on September 1, 1996, the Cutoff Date will be June 1, 1996 (90 days earlier). If the Cutoff Date is deleted, it will remain blank until October 1, 1996, when it will be set to July 1, 1996
Q: A user can choose to have documents and deletion stubs automatically deleted (purged) from their Notes database by setting the "Remove Documents Not Modified..." field. How is this value actually enforced by Notes?
A: A purge occurs only once per database at the purge interval time. Every time a database is opened, a check is made to see if any documents meet the purge criteria and, if so, the purge is performed, under the following circumstances:
1. Whenever a user double-clicks the icon of a database.
2. On all of the Name & Address Books (values in the NAMES= line of the NOTES.INI file), whenever it is programmatically opened for the first time, say, by a mail address lookup.
3. On the log database (LOG.NSF) and statistics database (STATREP.NSF), whenever they are programmatically opened.
4. On the server, on all databases, when the UPDALL task is run.
5. Whenever a change is made to the Purge Interval in the Replication Settings.
If the Purge Interval is set to 0 in the Replication Settings, the deletion stubs will be purged immediately. Any change to this field will initiate a purge event when the user clicks OK. This is true regardless of the location of the database (local or on the server).
IMPORTANT: If you place a checkmark next to "Remove Documents Not Modified in the Last" setting, and place a "0" in the Days field, all of the documents will be deleted from the database. Do not place a checkmark in that box; only change the number of days setting to "0."
Q: Which time field is used when deciding which documents to purge?
A: In the File, Document Properties dialog box, it is the time marked as "Modified." Programmatically, it is the "SequenceTime" field in the document's Originator ID (OID, identifies a particular revision of a note, regardless of location. In other words, every replica of a note has the same OID, but the OID changes when the note is modified).