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BLOB Field Size Limit And Logging

P: n/a
We have a new CRM application that uses a DB2 7.2 database.

Our users noted that the CRM application would not allow them to attach and
store any documents over 2 meg in size. When asked, the vendor claims that
this behavior is a limit of the DB2 system. We asked the vendor how we might
get around this issue since most of our user's documents are over the 2 meg
limit. The vendor said that by removing logging from the blob fields the 2
meg limit on documents would go away.

Is this true?

We are now wondering, if logging is not being done on the blob fields, and
we have a problem where we need to do a restore and roll-forward, will the
data (documents) stored in the blob fields be lost?

Is this true?

Our users store data in MS Word format, PDF format, TIF format, Power Point
format and many other types typically associated with customers and the
marketing function.

Any insight into this situation would be greatly appreciated.

Thanks,

John
Nov 12 '05 #1
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7 Replies


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"johnm" <jo***@matrixsg.com> wrote in message
news:11*************@corp.supernews.com...
We have a new CRM application that uses a DB2 7.2 database.

Our users noted that the CRM application would not allow them to attach and store any documents over 2 meg in size. When asked, the vendor claims that
this behavior is a limit of the DB2 system. We asked the vendor how we might get around this issue since most of our user's documents are over the 2 meg limit. The vendor said that by removing logging from the blob fields the 2
meg limit on documents would go away.

Is this true?

We are now wondering, if logging is not being done on the blob fields, and
we have a problem where we need to do a restore and roll-forward, will the
data (documents) stored in the blob fields be lost?

Is this true?

Our users store data in MS Word format, PDF format, TIF format, Power Point format and many other types typically associated with customers and the
marketing function.

Any insight into this situation would be greatly appreciated.

Thanks,

John

In DB2 LUW 8.2, logging of LOB columns is the default, but it can be
disabled for a particular column when the table is created. However, the
maximum size LOB than can be logged is 1 GB. I don't recall if the limit is
different for previous versions of DB2. If you have an previous version of
DB2 than is current, check the SQL manual for Create Table.

Keep in mind that such applications are usually written to work on multiple
databases, and there may a different restriction on a different database.
Nov 12 '05 #2

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Mark A wrote:
In DB2 LUW 8.2, logging of LOB columns is the default, but it can be
disabled for a particular column when the table is created. However, the
maximum size LOB than can be logged is 1 GB. I don't recall if the limit
is different for previous versions of DB2. If you have an previous version
of DB2 than is current, check the SQL manual for Create Table.


In addition, LOBs can have a maximum size of 2GB in DB2 UDB.

--
Knut Stolze
Information Integration
IBM Germany / University of Jena
Nov 12 '05 #3

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Thank you both for the most valuable information. It is very helpful to me
when talking to the CRM application vendor.

Is it true that if the logging is disabled for a particular LOB column, all
of the objects in that LOB will be lost should a backup need to be resotred
to recover the database?

Thanks,

John
"Knut Stolze" <st****@de.ibm.com> wrote in message
news:d3**********@fsuj29.rz.uni-jena.de...
Mark A wrote:
In DB2 LUW 8.2, logging of LOB columns is the default, but it can be
disabled for a particular column when the table is created. However, the
maximum size LOB than can be logged is 1 GB. I don't recall if the limit
is different for previous versions of DB2. If you have an previous version of DB2 than is current, check the SQL manual for Create Table.


In addition, LOBs can have a maximum size of 2GB in DB2 UDB.

--
Knut Stolze
Information Integration
IBM Germany / University of Jena

Nov 12 '05 #4

P: n/a
You will lose the LOB column only if you restore from online backup.
You will not while restoring from offline backup.

Nov 12 '05 #5

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You will lose the LOB column only if you restore from online backup
(with logging off). You will not while restoring from offline backup.

Nov 12 '05 #6

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Thanks for the information.

You have been most helpful and I appreciate it!

John
"Visu" <Vi*******@gmail.com> wrote in message
news:11*********************@g14g2000cwa.googlegro ups.com...
You will lose the LOB column only if you restore from online backup
(with logging off). You will not while restoring from offline backup.

Nov 12 '05 #7

P: n/a
Thanks so much for the help!

You have provided some very valuable information.

Thanks,

John
"Visu" <Vi*******@gmail.com> wrote in message
news:11*********************@g14g2000cwa.googlegro ups.com...
You will lose the LOB column only if you restore from online backup
(with logging off). You will not while restoring from offline backup.

Nov 12 '05 #8

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