XML DB2 9 DASD space issues

George Palko

XML DB2 9 DASD space issues
Hi List,

We recently completed a pilot project that involved converting a BLOB which was 6.1 volumes in size to XML. After the conversion, the XML table expanded to 25.1 volumes. We then did a reorg to reclaim space; afterwards the XML table was about 7.7 volumes in size. We would like to convert other BLOBS. However, we are having issues with DASD. We have multiple BLOBS that exceed well over 100 volumes. To convert these in production and development we would need to support additional volumes for the conversion, such as sorting and mirroring which would necessitate 1500 additional volumes. This is a huge issue.

So, my question to the List is whether anyone knows of a way were compression can happen on the "insert" of the XML record as opposed to at Reorg time? I could easily see this becoming a larger issue as more companies convert their large object to XML.

Thank you,
George



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Mike Bell

Re: XML DB2 9 DASD space issues
(in response to George Palko)
I think your question is

If I build a table in a compressed tablespace can I get compression even I
haven't done a load or reorg.

The answer as I understand it is NO.

What you can do is convert some percentage of the data and then run the
reorg to establish the compression dictionary. This would require your
convert process to be smart enough to restart with the last processed blob.
Good programming practice but not everyone does it.

The other alternative is to convert a small amount of data, then run the
reorg, then delete the data with SQL which will leave the compression
dictionary in place. Then run the entire conversion.

Mike
HLS Technologies


-----Original Message-----
From: IDUG DB2-L [mailto:[login to unmask email] On Behalf Of Palko, George
Sent: Wednesday, December 09, 2009 1:54 PM
To: [login to unmask email]
Subject: [DB2-L] XML DB2 9 DASD space issues

Hi List,



We recently completed a pilot project that involved converting a BLOB which
was 6.1 volumes in size to XML. After the conversion, the XML table expanded
to 25.1 volumes. We then did a reorg to reclaim space; afterwards the XML
table was about 7.7 volumes in size. We would like to convert other BLOBS.
However, we are having issues with DASD. We have multiple BLOBS that exceed
well over 100 volumes. To convert these in production and development we
would need to support additional volumes for the conversion, such as sorting
and mirroring which would necessitate 1500 additional volumes. This is a
huge issue.



So, my question to the List is whether anyone knows of a way were
compression can happen on the "insert" of the XML record as opposed to at
Reorg time? I could easily see this becoming a larger issue as more
companies convert their large object to XML.



Thank you,

George

CONFIDENTIALITY NOTICE: The Ohio Public Employees Retirement System intends
this e-mail message, and any attachments, to be used only by the person(s)
or entity to which it is addressed. This message may contain confidential
and/or legally privileged information. If the reader is not the intended
recipient of this message or an employee or agent responsible for delivering
the message to the intended recipient, you are hereby notified that you are
prohibited from printing, copying, storing, disseminating or distributing
this communication. If you received this communication in error, please
delete it from your computer and notify the sender by reply e-mail.


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_____________________________________________________________________

* IDUG North America * Tampa, Florida, * May 10-14 2010 * http://IDUG.ORG/NA *
_____________________________________________________________________

http://www.idug.org/db2-content/index.html has THOUSANDS of free technical presentations!
DB2 LUW, DB2 z/OS, Performance, Installation, Tuning, Coding, BI, Warehouses, - among
many more categories of help waiting for you!
Whether you are an old hand or a DB2 newbie, we have presentations for every level.
_____________________________________________________________________

If you need to change settings, http://www.idug.org/cgi-bin/wa?A0=DB2-L is the home of IDUG's DB2-L