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Observation: Index Access for Large Result Set
Add the local predicate OR 0=1 to prevent the Db2 optimizer from invoking index access against a large result set. Instead, the optimizer will invoke a tablespace scan which does not require reading both the index and the data pages.
The example below adds OR 0=1 to the third predicate to make column C2 non-indexable.
SELECT
*
FROM
T1
WHERE
C3 = 123 AND
C1 = 5 AND
(C2 = 7 OR 0=1)