sortwork allocation

Melissa Case

sortwork allocation
Hello,
We're having a debate about our sortwork files....

Should we allocate all our files (50+) to the same size on DASD?
What is the best SEGSIZE for our Sortwork files?
How many 4k to 32k files should we have? We have many 32k, but the
resource unavailable messages routinely appear on the 4k datasets.

The documentation on this subject is sparse, so we're asking the pros! :)

Thanks
Missy Case
CSG International

Aurora Emanuela Dellanno

RE: sortwork allocation
(in response to Melissa Case)

hey Missy! *waves*

 

we recently had a ding dong about work files - and aside from the question of what version of DB2 are you on, the other question is, do you always preallocate workfiles?

 

Thanks.

 

Aurora

 

PS stay safe and healthy

NB black lives matter

Roy Boxwell

sortwork allocation
(in response to Melissa Case)
Hi!



Check out the recent archives – there was a fair amount of traffic all about work/sort and ZPARM settings (SRTPOOL for example to avoid using the workspace completely)



This was the email heading:



Db2 12 z/OS 2.4 - all my volumes are being ET UP by 32k workfiles!







Roy Boxwell

SOFTWARE ENGINEERING GmbH and SEGUS Inc.
-Product Development-

Vagedesstrasse 19
40479 Dusseldorf/Germany
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Software Engineering GmbH
Amtsgericht Düsseldorf, HRB 37894
Geschäftsführung: Gerhard Schubert, Ulf Heinrich



From: melissa case <[login to unmask email]>
Sent: Tuesday, June 16, 2020 4:15 PM
To: [login to unmask email]
Subject: [DB2-L] - sortwork allocation



Hello,

We're having a debate about our sortwork files....



Should we allocate all our files (50+) to the same size on DASD?

What is the best SEGSIZE for our Sortwork files?

How many 4k to 32k files should we have? We have many 32k, but the resource unavailable messages routinely appear on the 4k datasets.



The documentation on this subject is sparse, so we're asking the pros! :)



Thanks

Missy Case

CSG International





-----End Original Message-----

Attachments

  • smime.p7s (5.1k)

Jorg Lueke

RE: sortwork allocation
(in response to Roy Boxwell)

What segsize could be better than 16? Usually if it looks like the workfiles need a bit more space I go with the greater of 2GB or the existing file sizes. If the first two are old any tiny I've never gone and resized them to match the later ones.

Jorg Lueke Db2 Sysprog

https://www.linkedin.com/in/jorg-lueke-8b391b4/

Melissa Case

sortwork allocation
(in response to Aurora Emanuela Dellanno)
Aurora! Hey, nice to hear from you - sorry for the lack of information -

we DO always allocate our sortwork files, we're DB2 V12 catalog is FL500
code level is 505.
Thanks!
Missy Case
CSGInternational

On Wed, Jun 17, 2020 at 2:41 AM Aurora Emanuela Dellanno <
[login to unmask email]> wrote:

> hey Missy! *waves*
>
>
>
> we recently had a ding dong about work files - and aside from the question
> of what version of DB2 are you on, the other question is, do you always
> preallocate workfiles?
>
>
>
> Thanks.
>
>
>
> Aurora
>
>
>
> PS stay safe and healthy
>
> NB black lives matter
>
> -----End Original Message-----
>

Lizette Koehler

sortwork allocation
(in response to Melissa Case)
Melissa –



DFSORT can calculate how much and how many SORTWKxx are needed.



I am curious why you do the allocation.



From what I have seen, DFSORT gets passed by DB2 functions a FILZ= parm. This tells DFSORT how much data to work with.



It actually can be under stated. For example – you have a 100m bytes of data going to the SORT, but only see FILZ=1M – it should not cause the SORT to fail. I have run tests and so far no matter how far off the FILZ was – Sort was able to adapt



What is driving the need to allocate SORTWKxx?



Lizette





From: melissa case <[login to unmask email]>
Sent: Wednesday, June 17, 2020 9:25 AM
To: [login to unmask email]
Subject: [DB2-L] - RE: sortwork allocation



Aurora! Hey, nice to hear from you - sorry for the lack of information -



we DO always allocate our sortwork files, we're DB2 V12 catalog is FL500 code level is 505.

Thanks!

Missy Case

CSGInternational



On Wed, Jun 17, 2020 at 2:41 AM Aurora Emanuela Dellanno <[login to unmask email] <mailto:[login to unmask email]> > wrote:

hey Missy! *waves*



we recently had a ding dong about work files - and aside from the question of what version of DB2 are you on, the other question is, do you always preallocate workfiles?



Thanks.



Aurora



PS stay safe and healthy

NB black lives matter



-----End Original Message-----



-----End Original Message-----

Melissa Case

sortwork allocation
(in response to Lizette Koehler)
I should clarify that the sortwork files are DSNDB07 tablespaces. Hence
the question about optimal SEGSIZE for them. It's a combination of all the
DB2 sortwork work that we're trying to calculate, we just wanted a best
practices option for 4k to 32k allocation (because we see more failures
[resource unavailable messages] on the 4k instead of the 32k workfiles), so
we decided to ask the DB2 community their successes for DSNDB07.

Thanks
Missy Case

On Wed, Jun 17, 2020 at 10:31 AM Lizette Koehler <[login to unmask email]>
wrote:

> Melissa –
>
>
>
> DFSORT can calculate how much and how many SORTWKxx are needed.
>
>
>
> I am curious why you do the allocation.
>
>
>
> From what I have seen, DFSORT gets passed by DB2 functions a FILZ= parm.
> This tells DFSORT how much data to work with.
>
>
>
> It actually can be under stated. For example – you have a 100m bytes of
> data going to the SORT, but only see FILZ=1M – it should not cause the SORT
> to fail. I have run tests and so far no matter how far off the FILZ was –
> Sort was able to adapt
>
>
>
> What is driving the need to allocate SORTWKxx?
>
>
>
> Lizette
>
>
>
>
>
> *From:* melissa case <[login to unmask email]>
> *Sent:* Wednesday, June 17, 2020 9:25 AM
> *To:* [login to unmask email]
> *Subject:* [DB2-L] - RE: sortwork allocation
>
>
>
> Aurora! Hey, nice to hear from you - sorry for the lack of information -
>
>
>
> we DO always allocate our sortwork files, we're DB2 V12 catalog is FL500
> code level is 505.
>
> Thanks!
>
> Missy Case
>
> CSGInternational
>
>
>
> On Wed, Jun 17, 2020 at 2:41 AM Aurora Emanuela Dellanno <
> [login to unmask email]> wrote:
>
> hey Missy! *waves*
>
>
>
> we recently had a ding dong about work files - and aside from the question
> of what version of DB2 are you on, the other question is, do you always
> preallocate workfiles?
>
>
>
> Thanks.
>
>
>
> Aurora
>
>
>
> PS stay safe and healthy
>
> NB black lives matter
>
>
> -----End Original Message-----
>
>
> -----End Original Message-----
>