Re: JT400/JDBC performance issues

["Mark Phippard" <MarkP@xxxxxxxxxxxxxxx>]

Dieter,

>> To get performance that bad it seems like it would have to have 
something
>> to do with the JDBC statements you are executing.  Are you using SQL 
Views
>> in your SELECT?  Generally, these perform worse than Tables on the 
iSeries.
>
> the diffrence is less than 0,1 sec

I will admit that I have never measured it and we only use Tables in our 
statements.  I am basing this on statements I have seen elsewhere that 
said when you use a View, the query optimizer is not able to take into 
account the indexes that are over the table and in some cases this will 
yield significantly worse performance.

Mark







Dieter.Bender@xxxxxxxxxxx (Dieter Bender)
Sent by: java400-l-bounces@xxxxxxxxxxxx
02/19/2003 04:48 AM
Please respond to Java Programming on and around the iSeries / AS400 
 
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        Subject:        Re: JT400/JDBC performance issues


Mark,

On Wednesday 19 February 2003 02:23, you wrote:
> Suresh,
>
> To get performance that bad it seems like it would have to have 
something
> to do with the JDBC statements you are executing.  Are you using SQL 
Views
> in your SELECT?  Generally, these perform worse than Tables on the 
iSeries.

the diffrence is less than 0,1 sec

>
> You do not mention how large your tables are or how many records you are
> selecting.
>
> Finally, once those issues are worked out, a big area where problems 
will
> occur with the iSeries is if you do not use Connection Pools. 
Establishing
> a connection to the iSeries has a high overhead.  Using a pool 
eliminates
> that problem.  However, we are talking seconds not minutes.

I've made measures on this, normally a connect shoul be < 0,3 sec and 
making 
800 connections to a little 270 should not be a problem. 
You should use connection pooling anyway, its easier to use for 
transaction 
handling and talking about web applications, you never know how many users 

wil connect, but in this case you won't see any improvement.

Dieter

>
> Hope this helps,
>
> Mark
>
>
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-- 
mfG

Dieter Bender


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