SEO

(DB2 V.8.1)

Hi @ll,

when i start my DB2 and my application connects and makes some SQL Tests
my system is running out of memory (UNITED LINUX 1.0) goes slow and
needs very very long time to answer my requests. When i kill my client
application all this used memory is killed so my application is not the
problem i think it is db2. My linux system(United Linux 1.0 inside DB2)
is runnning under an redhat 9 linux machine my United Linux is in vmware
emulated. But my vmware everything is ok enough memory and all other
machine ( 3 suse linux machines ) also working fine. It's only the
machine with DB2 installed.

Anybody an idea???

Cu @ll,

Fabian

P.S. THX FOR READING AND WRITING!!!

You haven't given enough information to even begin to guess what is
happening. I've run UDB on a 512mb Linux system but it requires
significant tuning to get reasonable performance. At this memory level;
the exact mix of software running has a significant impact on memory
available for UDB's use.

Your use of VMWARE adds another level of complexity to the performance
analysis. With three other systems running; I wonder how much real
memory you have allocated to the one running UDB. You state that this is
the only one running the database system which raises the question of
how much UDB tuning was done before running your queries.

Your queries are running long times but you don't give any details about
them. Did you run a query to retrieve a single row using an index or did
you join four large tables that don't have appropriate indexes to
support the join, forcing table scans and sorts? The EXPLAIN facility
will give you information about access paths and estimated (relative)
costs of running queries.

SHAPSHOTs run before and after your queries will also give you
information about what is happening when you run the queries. Query
traces can give even more detailed information.

Once you've figured out what is happening to make the queries run
slowly; you can make an intelligent decision about the remedy that is
needed.

Philip Sherman



hauger wrote:
> (DB2 V.8.1)
>
> Hi @ll,
>
> when i start my DB2 and my application connects and makes some SQL Tests
> my system is running out of memory (UNITED LINUX 1.0) goes slow and
> needs very very long time to answer my requests. When i kill my client
> application all this used memory is killed so my application is not the
> problem i think it is db2. My linux system(United Linux 1.0 inside DB2)
> is runnning under an redhat 9 linux machine my United Linux is in vmware
> emulated. But my vmware everything is ok enough memory and all other
> machine ( 3 suse linux machines ) also working fine. It's only the
> machine with DB2 installed.
>
> Anybody an idea???
>
> Cu @ll,
>
> Fabian
>
> P.S. THX FOR READING AND WRITING!!!

Bufferpools go into REAL RAM. With all your VMs etc,. you probably don't
have much of that.This will create a shortage of memory for everything else,
your system will start swapping everything else and performance will drop to
almost 0. Add real memory and allocate it to the VM, and/or shrink
bufferpools until you reach the best trade-off you can.

Also note that DB2 will always perform badly in a VM, as its designed to
optimize for real disks, not emulated disks.

"hauger" <F.Knopf@gmx.de> wrote in message
news:2uuptbF2epmirU1@uni-berlin.de...
> (DB2 V.8.1)
>
> Hi @ll,
>
> when i start my DB2 and my application connects and makes some SQL Tests
> my system is running out of memory (UNITED LINUX 1.0) goes slow and needs
> very very long time to answer my requests. When i kill my client
> application all this used memory is killed so my application is not the
> problem i think it is db2. My linux system(United Linux 1.0 inside DB2) is
> runnning under an redhat 9 linux machine my United Linux is in vmware
> emulated. But my vmware everything is ok enough memory and all other
> machine ( 3 suse linux machines ) also working fine. It's only the machine
> with DB2 installed.
>
> Anybody an idea???
>
> Cu @ll,
>
> Fabian
>
> P.S. THX FOR READING AND WRITING!!!

Mark Yudkin wrote:
> Bufferpools go into REAL RAM. With all your VMs etc,. you probably don't
> have much of that.This will create a shortage of memory for everything else,
> your system will start swapping everything else and performance will drop to
> almost 0. Add real memory and allocate it to the VM, and/or shrink
> bufferpools until you reach the best trade-off you can.
>
> Also note that DB2 will always perform badly in a VM, as its designed to
> optimize for real disks, not emulated disks.
>
> "hauger" <F.Knopf@gmx.de> wrote in message
> news:2uuptbF2epmirU1@uni-berlin.de...
>
>>(DB2 V.8.1)
>>
>>Hi @ll,
>>
>>when i start my DB2 and my application connects and makes some SQL Tests
>>my system is running out of memory (UNITED LINUX 1.0) goes slow and needs
>>very very long time to answer my requests. When i kill my client
>>application all this used memory is killed so my application is not the
>>problem i think it is db2. My linux system(United Linux 1.0 inside DB2) is
>>runnning under an redhat 9 linux machine my United Linux is in vmware
>>emulated. But my vmware everything is ok enough memory and all other
>>machine ( 3 suse linux machines ) also working fine. It's only the machine
>>with DB2 installed.
>>
>>Anybody an idea???
>>
>>Cu @ll,
>>
>>Fabian
>>
>>P.S. THX FOR READING AND WRITING!!!
>
>
>
Hi Mark,

i made this option and it has no effect. I tried this. I mofified this
variable Query heap size to 40 with the effect that it takes longer but
i will run out of memory and take the swap area. How can i set the
memory size used for DB2 didnt find anything about this. I dont think
that this problem is a vmware problem but i have not the real experience
in this.
Any clue here???

Cya,

Fabian

hauger wrote:
> Mark Yudkin wrote:
>
>> Bufferpools go into REAL RAM. With all your VMs etc,. you probably
>> don't have much of that.This will create a shortage of memory for
>> everything else, your system will start swapping everything else and
>> performance will drop to almost 0. Add real memory and allocate it to
>> the VM, and/or shrink bufferpools until you reach the best trade-off
>> you can.
>>
>> Also note that DB2 will always perform badly in a VM, as its designed
>> to optimize for real disks, not emulated disks.
>>
>> "hauger" <F.Knopf@gmx.de> wrote in message
>> news:2uuptbF2epmirU1@uni-berlin.de...
>>
>>> (DB2 V.8.1)
>>>
>>> Hi @ll,
>>>
>>> when i start my DB2 and my application connects and makes some SQL
>>> Tests my system is running out of memory (UNITED LINUX 1.0) goes slow
>>> and needs very very long time to answer my requests. When i kill my
>>> client application all this used memory is killed so my application
>>> is not the problem i think it is db2. My linux system(United Linux
>>> 1.0 inside DB2) is runnning under an redhat 9 linux machine my United
>>> Linux is in vmware emulated. But my vmware everything is ok enough
>>> memory and all other machine ( 3 suse linux machines ) also working
>>> fine. It's only the machine with DB2 installed.
>>>
>>> Anybody an idea???
>>>
>>> Cu @ll,
>>>
>>> Fabian
>>>
>>> P.S. THX FOR READING AND WRITING!!!
>>
>>
>>
>>
> Hi Mark,
>
> i made this option and it has no effect. I tried this. I mofified this
> variable Query heap size to 40 with the effect that it takes longer but
> i will run out of memory and take the swap area. How can i set the
> memory size used for DB2 didnt find anything about this. I dont think
> that this problem is a vmware problem but i have not the real experience
> in this.
> Any clue here???
>
> Cya,
>
> Fabian

The effect of your tuning effort should be minimal because Query Heap
Size will have little effect on your performance. You need to allocate
many tens to hundreds of megabytes to the buffer pools. Real memory must
be available to support the buffer pools because paging them eliminates
their performance benefits.

You still haven't specified anything about your system setup. How much
real memory did you allocate (using vmware) to the image running UDB?
Did you do any tuning of the buffer pools after installing UDB? Are you
logged on to the image using an X (GUI interface) terminal? Are you
running a Control Center on the UDB image? Have you altered other tuning
parameters to minimize db2 processes, freeing up more memory for buffer
pools?

The DB2 Configuration advisor is accessable from the control center. It
can help you with basic tuning.

You need to spend some time reading the "Administration Guide:
Performance" manual. Chapter 8, Operational Performance and Chapter 13,
Configuring DB2 have much information you will need to tune.
Unfortunately, manuals assume a significant amount of knowledge about
what things are and how they work. Vendor classes, college courses, and
published books are all useful to build your backround knowledge.

Philip Sherman

> I mofified this variable Query heap size to 40 with the effect that it
> takes longer but i will run out of memory and take the swap area.
Tweaking the query heap usually has minimal effect on total RAM usage. As I
said
>> Bufferpools go into REAL RAM
In other words, deal with the bufferpools. Details are in the manuals.

"hauger" <F.Knopf@gmx.de> wrote in message
news:2v0sitF2e03imU1@uni-berlin.de...
> Mark Yudkin wrote:
>> Bufferpools go into REAL RAM. With all your VMs etc,. you probably don't
>> have much of that.This will create a shortage of memory for everything
>> else, your system will start swapping everything else and performance
>> will drop to almost 0. Add real memory and allocate it to the VM, and/or
>> shrink bufferpools until you reach the best trade-off you can.
>>
>> Also note that DB2 will always perform badly in a VM, as its designed to
>> optimize for real disks, not emulated disks.
>>
>> "hauger" <F.Knopf@gmx.de> wrote in message
>> news:2uuptbF2epmirU1@uni-berlin.de...
>>
>>>(DB2 V.8.1)
>>>
>>>Hi @ll,
>>>
>>>when i start my DB2 and my application connects and makes some SQL Tests
>>>my system is running out of memory (UNITED LINUX 1.0) goes slow and needs
>>>very very long time to answer my requests. When i kill my client
>>>application all this used memory is killed so my application is not the
>>>problem i think it is db2. My linux system(United Linux 1.0 inside DB2)
>>>is runnning under an redhat 9 linux machine my United Linux is in vmware
>>>emulated. But my vmware everything is ok enough memory and all other
>>>machine ( 3 suse linux machines ) also working fine. It's only the
>>>machine with DB2 installed.
>>>
>>>Anybody an idea???
>>>
>>>Cu @ll,
>>>
>>>Fabian
>>>
>>>P.S. THX FOR READING AND WRITING!!!
>>
>>
>>
> Hi Mark,
>
> i made this option and it has no effect. I tried this. I mofified this
> variable Query heap size to 40 with the effect that it takes longer but i
> will run out of memory and take the swap area. How can i set the memory
> size used for DB2 didnt find anything about this. I dont think that this
> problem is a vmware problem but i have not the real experience in this.
> Any clue here???
>
> Cya,
>
> Fabian

Mark Yudkin wrote:
>>I mofified this variable Query heap size to 40 with the effect that it
>>takes longer but i will run out of memory and take the swap area.
>
> Tweaking the query heap usually has minimal effect on total RAM usage. As I
> said
>
>>>Bufferpools go into REAL RAM
>
> In other words, deal with the bufferpools. Details are in the manuals.
>
> "hauger" <F.Knopf@gmx.de> wrote in message
> news:2v0sitF2e03imU1@uni-berlin.de...
>
>>Mark Yudkin wrote:
>>
>>>Bufferpools go into REAL RAM. With all your VMs etc,. you probably don't
>>>have much of that.This will create a shortage of memory for everything
>>>else, your system will start swapping everything else and performance
>>>will drop to almost 0. Add real memory and allocate it to the VM, and/or
>>>shrink bufferpools until you reach the best trade-off you can.
>>>
>>>Also note that DB2 will always perform badly in a VM, as its designed to
>>>optimize for real disks, not emulated disks.
>>>
>>> "hauger" <F.Knopf@gmx.de> wrote in message
>>>news:2uuptbF2epmirU1@uni-berlin.de...
>>>
>>>
>>>>(DB2 V.8.1)
>>>>
>>>>Hi @ll,
>>>>
>>>>when i start my DB2 and my application connects and makes some SQL Tests
>>>>my system is running out of memory (UNITED LINUX 1.0) goes slow and needs
>>>>very very long time to answer my requests. When i kill my client
>>>>application all this used memory is killed so my application is not the
>>>>problem i think it is db2. My linux system(United Linux 1.0 inside DB2)
>>>>is runnning under an redhat 9 linux machine my United Linux is in vmware
>>>>emulated. But my vmware everything is ok enough memory and all other
>>>>machine ( 3 suse linux machines ) also working fine. It's only the
>>>>machine with DB2 installed.
>>>>
>>>>Anybody an idea???
>>>>
>>>>Cu @ll,
>>>>
>>>>Fabian
>>>>
>>>>P.S. THX FOR READING AND WRITING!!!
>>>
>>>
>>>
>>Hi Mark,
>>
>>i made this option and it has no effect. I tried this. I mofified this
>>variable Query heap size to 40 with the effect that it takes longer but i
>>will run out of memory and take the swap area. How can i set the memory
>>size used for DB2 didnt find anything about this. I dont think that this
>>problem is a vmware problem but i have not the real experience in this.
>>Any clue here???
>>
>>Cya,
>>
>>Fabian
>
>
>
Hi Mark,

it was a problem on my client application. DB2 works fine now. ;-)

Cu,

Fabian