Hi,

I've 10 large tables each have around 20 million records.
while retreiving queries using joining of 3 to 4 tables with some conditions, the execution takes very long time and performance become a concern.

What are the ways to improve the performance of the queries?
Actually the queries are for datawarehousing reports and joins more than 3 tables.

Please suggest on Indexing, table splits and any other ways to improve the performance.

MDCs, MQTs

I'm using db2v8. I'll try with MDC and MQT (I'm new to Db2 and need to search )
The tables are already created. Can the reorg of Indexes with Runstats help?

Creating some more indexes will improve the performance. Need to check what are the coloumns require the indexes.

How to see the index on which coloumns they are created?
I need to see the indexes and their keys.

db2 describe indexes for schema.table show detail

are the below queries give same result?

QUERY1:

SELECT A.DEPTNAME,
A.DEPTNO, A.BUILDING_NO,B.CALL_LETTERS, B.EMP_CITY]
FROM
ORG.DEPT A LEFT OUTER JOIN ORG.EMP B
ON
A.DEPTNO=B.DEPTNO
WHERE
(A.JOINING_DATE= '2005-01-01 11:16:30.0' OR
B.JOINING_DATE= '2005-01-01 11:16:30.0')


query2:

SELECT A.DEPTNAME,
A.DEPTNO, A.BUILDING_NO,B.CALL_LETTERS, B.EMP_CITY
FROM
ORG.DEPT A LEFT OUTER JOIN ORG.EMP B
ON
A.DEPTNO=B.DEPTNO
AND
A.JOINING_DATE= '2005-01-01 11:16:30.0'
OR
B.JOINING_DATE= '2005-01-01 11:16:30.0'