I have some questions. My company has investigation into implementing
an ERP solution based on the Unidata database. These questions are
varied, but if you can respond to any I would be forever in your debt.
I don't mind pros or cons, but would appreciate honesty, not
commercials. Thank you.

1) We have a solid, although not perfect system in place now. It is
mostly custom software on os400 using the os400 version of UDB. What
are the benefits or negatives to switching to the Unidata system?

2) We have no intention of changing our internet front end systems to
anything else, but would need to tie in to our "backend" database for
order fullfilment, etc. We use Java web services and servlets to
fullfill these request. Can I use standard JDBC to make calls to the
Unidata data? If not, what interfaces would I need to use?

3) From what I've read (including some Unidata documentation) the
performance of this database is not as good as a typical 1NF database.
If this is true, what is the benefit of moving to this system, if I am
already familar with 1NF issues such as indexing, joining, and the
like?

4) Given a database of approximately 100 gig, what type of performance
would we get from it?

5) Is the database single threaded? If so, is there any way to make it
multi-threaded without playing too many games?

Originally posted by Chris



Although this is a perfectly correct forum on which to ask these
questions, you'll probably get a better response by subscribing to the
U2 users list at http://www.oliver.com/lists/u2/



More UniData people actively participate in that mailing list server
than contibute to CDP.



Regards

Mike.


--
Posted via http://dbforums.com

On 14 Oct 2003 15:43:11 -0700, cfowler (AT) jwpepper (DOT) com (Chris) wrote:

You should repeat this on the U2 users listserver (as mentioned
elsewhere), but I will give you some stuff here.

Unidata is very stable and provide a good, solid mapping of the
MultiValue model including all of the programming environments etc.
it is not the fastest of the MV platforms, but is close enough, fully
featured, and again, very stable.

Most of our experience with Unidata is on Windows, AIX, and Linux with
Linux being the main platform we run in-house. We even run internet
hosted Unidata systems with web and terminal access over the internet
including stuff like multi-path connection failover, etc.

I will let others answer this directly as we tend to do things a bit
less layered. We have an http server that is implemented directly in
Unidata, so the JDBC glue does not apply in our case.

I don't think that this is somethat that you can make a blanket
statement like this on. The data model in Unidata is enough different
than 1NF that if you try to act like 1NF in Unidata, performance is
quite bad. On the other hand, if you try to make a 1NF database act
MultiValue, the performance is equally bad.

Remember that the MultiValue databases all have their roots in
business applicatoion running multi-user with incredibly slow
hardware. The 8MHz PC-AT would support 17 users with the original
native MultiValue systems.

This is large, but not huge. Also, in Unidata, it is likely a lot
smaller as Unidata is a very good at eliminating duplicate fields,
spare storage, etc.

Each process is single threaded, but multiple processes run
concurrently. SMP systems scale very well and concurrency locking
issues at the database level are rarely a performance issue. There is
a functional "background" processor.


In general, Unidata, and all the other MV solutions, are very "nuts
and bolts" products that are designed to present the data to the
programmer and user in a particular way. The native data model is
very flexible and can often map dozens of tables into a single "file".
Well designed applications usually do "direct" IO with hashed keys
that directly reference the data, usually in a single physical disk
operation.



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