Determining When to Purge the Delete Log Database

Calendar Server includes the Delete Log database (ics50deletelog.db ) to store deleted events and todos (tasks). Connector for Microsoft Outlook and other third-party clients make use of the Delete Log database when synchronizing with the Calendar Server. When a sync is performed, the Delete Log database provides Connector for Microsoft Outlook the list of deleted entries which are then deleted by Connector for Microsoft Outlook. Administrators have the option ( service.admin.purge.deletelog parameter) of setting up Calendar Server to automatically purge the entries in the Delete Log database. The caldb.berkeleydb.purge.deletelog.beforetime parameter specifies a time before which to purge entries in the Delete Log database. Problems may arise if, for example,service.admin.purge.deletelog is set to yes and caldb.berkeleydb.purge.deletelog.beforetime is set to the default of 518400 seconds (6 days), but a user takes a 14 day vacation. When the user returns from vacation and syncs Connector for Microsoft Outlook with Calendar Server, the Delete Log database contains deleted entries from the last 6 days. Outlook Connector will not delete those entries which have been purged from the Calendar Server since the previous Connector for Microsoft Outlook sync.

It is recommended that Calendar Server administrators change the parameter to 2592000 (30 days) if Connector for Microsoft Outlook is used as a clients. If a 30 day interval does not provide enough time, then administrators should change the parameter to a value that is more appropriate. For example, if employees commonly take 90 day vacations, the parameter should be changed according to the company model.

It is important to take into consideration the size to which the Delete Log database can grow within the time frame that the caldb.berkeleydb.purge.deletelog.beforetime is set. The size can be estimated based upon the number of users, average deleted events per day, and average size of a single Delete Log record. A simple formula of (users x events x record_size) can be used to estimate the size. For example, at a site with 1000 users, where the average number of events deleted per user per day is 20 and the average Delete Log record is 2 bytes, the size of the Delete Log database may potentially grow to 40000 (1000 x 20 x 2) bytes per day and 1200000 bytes in 30 days.

For details about the Delete Log database, see Chapter 18, Administering the Delete Log Database, in Sun Java System Calendar Server 6 2005Q4 Administration Guide.