ILM Implementation

An underlying design principle of the ILM implementation is based on the concept that the age of the data may not only be used as a criterion to determine when a record must be archived. There must be business rules which dictate that some records are still current and must not be archived.

ILM enabled tables have two additional columns - ILM Date (ILM_​DT) and ILM Archival Switch (ILM_​ARCH_​SW). The ILM Date is used to group the data by age during partitioning. The ILM Archival Switch is set by a background process when the record meets the business rules specific to the maintenance object and is eligible for archival. The ILM Archival Switch allows the database administrator (DBA) to check whether all records in a partition meet the business criteria defined for archival. If the ILM Archival Switch is set to Y for all records, then the DBA can take the required steps to archive the table partition.