Re: MS SQL Server JDBC connections

Chris,

Price, Chris wrote:

Thanks for the reply guys, but the problem is occurring after the JVM has
started - my timings are generated in the main method being executed. Before
creating the SQL Server connection, which is what seems to hang, an iSeries

JDBC connection is already created, which is much quicker.

I think the problems are either:
- something to do with the SQL Server JDBC driver, (perhaps a property needs
setting somewhere).
- are network related (but since both the iSeries and development PC's are
on the Lan and the SQL server is in a DMZ, I would have though that the
connection speeds would be similar.)
- resource related - it just happens to be at this point the jvm runs out of
memory and starts asking for more? (does anyone have any tuning pointers?)

Once the connection created the actual data transfers take roughly the same
amount of time.

Regards,
Chris.


-----Original Message-----
From: wdsci-l-bounces@xxxxxxxxxxxx [mailto:wdsci-l-bounces@xxxxxxxxxxxx] On
Behalf Of Vernon Hamberg
Sent: 22 February 2006 13:51
To: Websphere Development Studio Client for iSeries
Subject: Re: [WDSCI-L] MS SQL Server JDBC connections

Glad to see I'm not crazy - oh, well, might be, but was right on this one, anyway. Seems CRTJVAPGM does not affect JVM startup - makes sense - it is really about shortcutting the JIT kind of thing (I'm probably saying that wrong in some way, but do you get the idea?). The JVM startup is not based on any of the created Java program objects, what it is doing is the security and other authentication, the more classes, the longer. At least, according to my colleague across the aisle.

We found one way to get around this is to use an NEP to do the Java stuff. Definitely do NOT start new jobs for every Java evocation, and the same goes for client/server kinds of things that often fire off a new thread of job.

HTH
Vern

At 07:36 AM 2/22/2006, you wrote:

I tried some jave, and it happens exactly what vernon said, firs time the
job start the JVM, second and other time time was very good
----- Original Message -----
From: "Vernon Hamberg" <vhamberg@xxxxxxxxxxx>
To: "Websphere Development Studio Client for iSeries"

<wdsci-l@xxxxxxxxxxxx>

Sent: Wednesday, February 22, 2006 2:26 PM
Subject: Re: [WDSCI-L] MS SQL Server JDBC connections

A maybe - the JVM on the iSeries has not started up, so it has to go
through its initial authentication. This always takes a long time.
Whereas, in Eclipse, your JVM is already running. Consider how long
it takes to start up Eclipse.

So can you try doing the extract twice in one program (or job on the
iSeries)? The second should be faster if my theory is anywhere close.

HTH
Vern

At 04:38 AM 2/22/2006, you wrote:

All,



I have a JDBC based application that is extracting data from an iSeries
database, and writing it out to an MS SQL Server database. In eclipse

on

my

PC a simple extract takes about 5 secs. However when I move the code

onto

the iSeries, the same extract takes 55 secs, a 10 fold increase.

Changing

the iSeries database driver from jt400 to db2 makes no difference.

Running

crtjvapgm on all the jar's makes no difference.



Looking at my log output, most of the time is spent creating the SQL

server

connection. Why would this take so long on the iSeries, but be

practically

instantaneous on my PC? (The SQL server database is not local to my PC
either, it's on the other side of a firewall). I'm using the MS

sqljdbc.jar

I downloaded from the MS website. Are there some tuning options I can

play

with? Is there a better jar to use?



Anyone else had this problem?



Regards,

Chris.


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