The processing time for a constrained delete (DELETE...WHERE) can increase when:
- The DELETE does not meet the conditions for a fastpath delete processing. See Unconstrained Fastpath Delete Processing.
- The FALLBACK option is specified for the table, because the rows in the secondary copy of the table must also be deleted.
- Secondary indexes are defined for the table, because the secondary index subtable also must be updated to account for the rows deleted.
Processing time for a constrained delete can be shortened by specifying a primary index value, a USI value, or a highly selective NUSI value as the conditional expression of the WHERE clause.