Large number of open-DB-connections and the AS/400

[Herman]

We are busy consolidating a large number of AS/400's to one central machine
with one large database. I expect there to have 300 users active through a
Java application with JDBC which all will have 6 connections open, so this
results in 3000 open-DB-connections. I was wondering are there any
limitation in open-DB-connections? Or do I have to size the system in a
particular way? Anyone any experience with this matter?

Thanks,
Herman.

[Mark Megerian]

Generally you would make an attempt to create a connection pool. Then the
users take an entry
from the pool only when needed. This technique can reduce the number of active
connections
significantly. The December 1999 issue of News/400 magazine has a JDBC article
that contains
examples on how to use connection pooling. We do have experience with large
apps like you
describe, but 3000 active connections is on the high side. Would they all be
originating from
a single AS/400 job? If so, you may start to approach the single job limit of
40,000 handles.
While there is no specific limit on the number of connections, the handle limit
would be hit if your
3000 connections were all originating from one job, and each had a reasonable
number of active
statements.

Another thing to consider is that since most of the work will occur in the
QSYSWRK subsystem, check
to see that your pool allocations are adjusted accordingly. I have seen cases
where the allocations were
made with the expectation that the database work would be done in QINTER or
QBATCH, and those
were assigned to a different storage pool than QSYSWRK.

[Herman]

Mark,

thanks for your reaction, this sounds good to me. I've found the december
issue of 99 and I'll see what I can do with that.
The connections are all made from 600 different PC's which use the same
application and the same userprofile. If this is of any matter please let me
know.
Thanks so far,

Herman.
"Mark Megerian" <mege...@us.ibm.com> wrote in message
news:39BD37A6...@us.ibm.com...

[Fred Kulack]

Is the application that makes the connections running on the AS/400 serving
the PCs
OR
is an instance of the application that makes the connections running on each
of the 600 PCs?

If the prior, then this sounds like the perfect example of an application
that can use connection pooling to its fullest extent.

If the later, not so much...

--
Fred A. Kulack - AS/400e Java and Java DB2 access, Jdbc, JTA, etc...
IBM in Rochester, MN (Phone: 507.253.5982 T/L 553-5982)
mailto:kul...@us.ibm.com Personal: mailto:kul...@bresnanlink.net
AOL Instant Messenger: Home:FKulack Work:FKulackWrk
"Herman" <hel...@chello.nl> wrote in message
news:8pjhtm$cnv$1...@weber.a2000.nl...

[Kent Milligan]

I'd also strongly recommend the DB2 UDB for AS/400 SQL Performance Workshop as
part of your project. Just take the "Education" link off the DB2 UDB for AS/400
home page (ibm.com/as400/db2)

--
Kent Milligan, DB2 & BI team
PartnerWorld for Developers, AS/400
km...@us.removethis.ibm.com GO HAWKEYES!!
(opinions stated are not necessarily those of my employer)

[Herman]

The application itself is running on 200 PC-servers which are connected
through JDBC to the AS/400 databases.
From our developers I understood that a connection is made at
database-level. As we have 350 databases pooling is not really an option
because that means I would have to make 350 pools. So my question still is:
can I have 3000 connections open on a AS/400 model 820?
If you have any idea, please let me know,

Herman.
"Fred Kulack" <kul...@us.ibm.com> wrote in message
news:8pld5f$t9s$1...@news.rchland.ibm.com...