Observation: Cascading DELETE

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Observation: Cascading DELETE

A DELETE which invokes a CASCADE constraint might cause performance problems on large tables, especially if DB2 propagates the DELETE to several tables. To improve DELETE performance, consider the following:

Ensure indexes exist on the foreign keys. Without an index, deleting a row from the parent table requires a scan of each dependent table for which an index does not exist.
If rows in the parent table are frequently deleted and there are indexes defined for the foreign keys, place dependent tables to which deletes are cascaded into the same tablespace.