Table Management (Alarm Database Logging)

AlarmWorX64 Logger logs alarm data to one master active table. If no restrictions are placed on the size of the active table, then logging will continue to go to the active table as long as the AlarmWorX Logger is running. If, however, a restriction is placed on the size of the active table, then all logged data beyond the active table size will get logged to archive tables. The archive tables also have a maximum size determined by a number of records or time interval. When one archive table is full, archiving goes on to the next table. When all archive tables are full, the oldest archive table is deleted and a new one is set up. The name of each archive table is the name of the active table followed by the date and time of the first alarm in the table. In this system, the Active Table will always have the most recent alarm data. All these settings are set in the Table(s) Management sub-tab of the Database Logging tab on the AlarmWorX64 Logger Alarm Log Configuration Form. For additional information about this form, refer to Configuring the Logger.

Fields on the Table(s) Management sub-tab are:

Table Name Enter the name of the active table to log data to.
Active Table Here you can specify a limit on the active table size. The limit can be by the Maximum Number of Records, or by the Maximum Time Interval (select from hours, days, months, or years by clicking the ellipsis button ).

If both items are checked, then the table is full when the first of those two conditions is met. The Interval refers to the time difference between the first item logged (not the logging start time) and the most recent item logged. If neither item is checked, then no archiving will take place.

Archive Tables In this section, you can specify the quantity of archive tables and the condition(s) upon which each archive table is full.
Snapshots Table This section allows you to create a "snapshot" table that can be used to replay alarm data. In the Snapshots Period field, specify how often (in hours) a snapshot table can be created. A snapshot period value of 0 (zero) means that no snapshot table will be created. For data replay to work with alarms, the value of the snapshot period must be greater than 0.

Note: If, in the Archive Table(s) section, the Max Records and Max Interval fields are both left unchecked, then all archiving will go to one archive table of theoretically unlimited length, as no restrictions have been placed on the table size. In essence, the Max Tables field will be ignored.

During runtime, the Alarm Logger will create the active table if it does not exist and will also add any columns to the table if they are missing. The Logger will not create any indexes. Use a database administration tool to add indexes to columns that are searched and/or sorted by queries.