performance with repeated sql query

[Hartmut . Luttermann]

Hi, I have written a test program to measure the performance of the SAP DB. It repeats the following query SELECT  p.id FROM P p, A a  WHERE p.is_def = false  AND a.role='test_role'  AND a.type=1  AND a.name='test'  AND p.id=a.id  AND p.state=3 on table P and A. Table P contains ca. 850000 entities. The result of the query will contain ca. 10000 entities. p.id is defined as varchar (255) and there is an index on p.is_def and on p.state.   The surprise is that the query takes different times from loop to loop. It changes between 9s and 30s.   The test program runs in the Jboss-ApplicationServer in a stateless session bean which manages the DB connection. The DB runs on another machine, so it will not be disturbed by JBoss.   Hartmut Luttermann