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From Sunitha Kambhampati <ksunitha...@gmail.com>
Subject Re: [jira] Updated: (DERBY-959) Allow use of DRDA QRYDTA block sizes greater than 32K
Date Tue, 13 Jun 2006 16:25:52 GMT
Army wrote:

> Bryan Pendleton wrote:
>
>> Why did you pick 10 Meg as the new max value? Was that arbitrary, or 
>> does it derive from some other fundamental limit?
>
>
> In the DDM manual that I have (version 3 volume 3, which I think is 
> from 2004) the max value for QRYBLKSZ is listed as "MAXVAL 10,485,760 
> (10M)".  Also, in the DRDA manual for the same year, under the heading 
> "Simplified Query Processing Rules", there's the following quote:
>
> "Blocking applies only to the QRYDTA reply objects.  Each query block 
> is a QRYDTA DSS. The maximum query block size value allowed in the 
> qryblksz parameter is increased from 32K to 10M, thus accommodating 
> the larger data volumes required by modern, more data-intensive 
> applications."
>
> I'm not sure if these are the most recent versions of the manuals, but 
> I think this is probably where the 10M limit comes from...
>
Thanks Bryan and Army for looking at this.

Yes, the 10M was picked because it is the maximum query block size 
allowed per the spec.  The Version 3 specs are the latest specs after 
looking at the development history of the spec on the opengroup site. 
https://www.opengroup.org/projects/drda/uploads/40/9359/history.htm  and 
they are from 2004. http://www.opengroup.org/bookstore/catalog/c043.htm  
this is the link that I can get to to download the specs and it has 
version 3.

I'll also update the notes on the jira.

Thanks,
Sunitha.



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