You can use the EXPLAIN statement to display the selected search strategy.
CATALOG SCAN USING USER EQUAL CONDITION
DIFFERENT STRATEGIES FOR OR-TERMS
EQUAL CONDITION FOR INDEX (SUBQ)
EQUAL CONDITION FOR KEY COLUMN
EQUAL CONDITION FOR KEY COLUMN (SUBQ)
JOIN VIA MULTIPLE INDEXED COLUMNS
JOIN VIA RANGE OF MULTIPLE INDEXED COL.
JOIN VIA RANGE OF MULTIPLE KEY COLUMNS
NO STRATEGY NOW (ONLY AT EXECUTION TIME)
RANGE CONDITION FOR KEY COLUMN
RANGE CONDITION FOR KEY COLUMN (SUBQ)
RANGE CONDITION FOR INDEX (SUBQ)