I'm a "newbie" in sapdb, so maybe my answer doesn't make any sense.. ;-)
anyway:
I would expect for the first interaction a bigger delay (access path generation, more I/O to fill the bufferpools).
For the following interactions, the time should be aproximately equal (if you have enough buffers for the data; remember: your buffers are normally managed thru a LRU - Least recently used - algorith. If you don't have enough buffers, you'll have more I/O).
And don't forget to check if another process also needs resources from sapdb while your program runs.
Rodney
[EMAIL PROTECTED] wrote:
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
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