DB2 9 Parameter hell

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Roger Eriksson - 19 Dec 2006 12:24 GMT

I did set up this thing and it worked well during my test so I invited the
users to test it before it would be put into production. I got no complaits
and thought it all was working.

So I decided to run the Configuration advisor in the Control center and
applied their suggestions. I don't know if that was what made all the
difference but now I get all sorts of problems, not entirely sure that .

The two different errors I get now is SQL1478W-01626 and SQL1084C-57019
errors.

Especially QMF is giving me troubles with the codes 1084-57019. It seems
like the few first lucky users get in but then the memory

DB2 UDB 9.1.0 Linux x8664 on Red Hat 4 ES x64 on a Dell 2950 with two 3 GHz
dual core xeon and 8 Gb RAM. There are about 15 databases. Most of them are
small and rarely used. There are 3 or 4 that's used daily and they are on 1
to 10 Gb in size. The databases were backuped from DB2 v8.2 on a 32 bit
Linux server and restored and migrated on this one.

Anyone who can point me at what to look at? I've been surfing the web
trying to find out what to do but found nothing that solved my problem.

Is there a guide or software that could aid me in the search for the
optimal settings on this thing? Actually, att this point I would settle for
a working configuration.

I'm out of ideas and anything that would give me a new angle would be
appreciated.

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Mvh

/RE

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Liam Finnie - 19 Dec 2006 14:04 GMT

> I did set up this thing and it worked well during my test so I invited the
> users to test it before it would be put into production. I got no complaits
[quoted text clipped - 31 lines]
>
> /RE

Hello,

There are a few main things you can look at.

The first is your Linux kernel shared memory settings, in particular,
the shmall setting. This limits the total amount of shared memory that
can be allocated on the box. You'll probably want to set this close to
the amount of RAM on your machine. You can check out the following
link for other important kernel tuneables:

http://publib.boulder.ibm.com/infocenter/db2luw/v9/index.jsp?topic=/com.ibm.db2.
udb.uprun.doc/doc/t0008238.htm

The second, make sure you're using the 64-bit version of DB2, so you
can make use of all 8GB of RAM.

The third is to look at your memory configuration for all your
databases. Is there a strong requirement to have 15 separate
databases? In general, you'll probably get much better performance
(and much simplified administration) by having one single large
database (maybe using 15 different schemas?) than many smaller
databases. Did you run the configuration advisor on all 15 databases?
If so, you should probably run the config advisor again, ensuring that
you choose a suitable memory limit (mem_percent) for each database -
probably somewhere between 10-15% of RAM for each of the 4 commonly
used databases (the default mem_percent is 25). For the least-commonly
used databases, you should probably use somewhere between 2-5% of RAM.

Hope this helps.

Cheers,
Liam.

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Jeroen van den Broek - 19 Dec 2006 14:59 GMT

> I did set up this thing and it worked well during my test so I invited the
> users to test it before it would be put into production. I got no complaits
[quoted text clipped - 25 lines]
> I'm out of ideas and anything that would give me a new angle would be
> appreciated.

Next to the link provided by Liam, you might also want to check this
article:
http://www-128.ibm.com/developerworks/db2/library/techarticle/dm-0406qi/index.html

and perhaps also this redbook:
http://www.redbooks.ibm.com/abstracts/SG246432.html?Open

HTH.

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Jeroen

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Roger Eriksson - 09 Jan 2007 10:46 GMT

Thanks to both of you for answering.

It turned out to be a really simple translation misinterpretation. When I
read the original English documentation it all got clear(er) to me.

Instead of giving the database manager 80% of the systems resourses I tried
to give each of the databases 80%. And, well, trying to allocate 1200%
didn't really work so...

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Mvh

/RE

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Serge Rielau - 09 Jan 2007 13:14 GMT

> Thanks to both of you for answering.
>
[quoted text clipped - 4 lines]
> to give each of the databases 80%. And, well, trying to allocate 1200%
> didn't really work so...

Roger, what was the original language? Also would you mind using the
feedback button on your docs to help prevent others from having the same
experience?

Cheers
Serge

Signature

Serge Rielau
DB2 Solutions Development
IBM Toronto Lab

WAIUG Conference
http://www.iiug.org/waiug/present/Forum2006/Forum2006.html

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