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Observation: Hybrid Join Invokes Sort for Inner Join
You coded a hybrid join, requiring DB2 to sort at least two tables. DB2 combines the index entry RIDs from the qualifying inner table with the columns of the outer table to form an intermediate table. DB2 then sorts both the inner table RID list and the intermediate table.
The following example includes a hybrid join.
SELECT
A.deptno, A.deptname, A.mgrno, B.lastname
FROM T1 A,
T2 B
WHERE A.mgrno = B.empno;
Consider recoding the inner join as a full outer join, to remove the hybrid join, eliminating at least one sort.
SELECT
T1.deptno, T1.deptname, T1.mgrno, T2.lastname
FROM T1
FULL OUTER JOIN T2
ON T1.mgrno = T2.empno;