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db2diag.log not writing

P: n/a
We are on IBM DB2 7.1 ON WINDOWS. The db2diag.log is not working and
no new line written into it for few days. The last lines in
db2diag.log shows:

Warning: active log held by dirty pages.
Decrease softmax and/or increase num_iocleaners.
repeatedly . What is the problem? How can resolve it quickly? The
applicatipna dnLDAP is up and running though.

Please advise
Nov 12 '05 #1
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7 Replies


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"Shawn" <fa***************@yahoo.com> wrote in message
news:ab**************************@posting.google.c om...
We are on IBM DB2 7.1 ON WINDOWS. The db2diag.log is not working and
no new line written into it for few days. The last lines in
db2diag.log shows:

Warning: active log held by dirty pages.
Decrease softmax and/or increase num_iocleaners.
repeatedly . What is the problem? How can resolve it quickly? The
applicatipna dnLDAP is up and running though.

If you click on Start/Programs/IBM DB2/Information/DB2 Information, you
should get a combined book index and search engine. Go to the search engine
and enter "num_iocleaners" (without the quotes) and click the Search button.
Assuming your documentation is similar to mine - I'm running DB2 V7.2, FP9 -
your first hit should be an article in the Administration Guide called
"Managing the Database Buffer Pool". If you read that, you will get a good
explanation of what is happening within your system; "dirty pages",
"num_iocleaners", and "softmax" are all explained.

You haven't said what level of experience you or your shop have had with DB2
so I'm going to take a wild guess that you don't have a lot of experience.
(Forgive me if I've guessed wrong!). Is it possible that your applications
haven't issued a COMMIT in a while? That would be the most obvious reason
why you have too many dirty pages. Remember, your applications need to issue
COMMIT statements occasionally to confirm to DB2 that you really want to
keep the updates, inserts and deletes you've been making; otherwise, DB2
only makes the changes in the applications work area and the bufferpool but
doesn't make them to the database proper in case you want to ROLLBACK (undo)
the changes. This causes an accumulation of dirty pages (data that has been
changed but not committed) which will eventually bring the system to its
knees if not handled.

Please note that there are a variety of events which cause COMMITs to happen
other than explicit COMMIT statements within your applications. For example,
a program that ends normally will issue its own commit automatically.
However, you could have a situation where a program is stuck for some
reason - waiting for input? waiting for a file to be released? - that has
kept it from getting to the end. Therefore, waiting until the automatic
COMMIT point may not be an option for you. Or maybe it is; if you give the
input or file the application is waiting for, you may solve the problem.

It is also possible that you have misconfigured NUM_IOCLEANERS or SOFTMAX so
that they aren't appropriate for your system. Both are parameters associated
with a specific database - as opposed to DB2 in its entirety - so you can
see your values with the command:

db2 get db config for <database-name> | more

You can issue this command from a DB2 Command Window. Then, if the values
are inappropriate (the article I mentioned should help you set appropriate
values), you can modify the values with the UPDATE DB CONFIG command. For
example:

db2 update db config for <database-name> using softmax 150

[See the Command Reference for details of the GET DATABASE CONFIGURATION and
UPDATE DATABASE CONFIGURATION commands.]

Rhino
Nov 12 '05 #2

P: n/a
Shawn wrote:
We are on IBM DB2 7.1 ON WINDOWS. The db2diag.log is not working and
no new line written into it for few days. The last lines in
db2diag.log shows:

Warning: active log held by dirty pages.
Decrease softmax and/or increase num_iocleaners.
repeatedly . What is the problem? How can resolve it quickly? The
applicatipna dnLDAP is up and running though.


What's your setting for the DBM CFG parameter named DIAGLEVEL? The default
is 3.

db2 get dbm cfg | more

Also, do you have enough disk space on the file system where the db2diag.log
is supposed to be written to? If the disk is full, db2 can't append to the
db2diag.log.

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

P: n/a
Knut Stolze <st****@de.ibm.com> wrote in message news:<cf**********@fsuj29.rz.uni-jena.de>...
Shawn wrote:
We are on IBM DB2 7.1 ON WINDOWS. The db2diag.log is not working and
no new line written into it for few days. The last lines in
db2diag.log shows:

Warning: active log held by dirty pages.
Decrease softmax and/or increase num_iocleaners.
repeatedly . What is the problem? How can resolve it quickly? The
applicatipna dnLDAP is up and running though.


What's your setting for the DBM CFG parameter named DIAGLEVEL? The default
is 3.

db2 get dbm cfg | more

Also, do you have enough disk space on the file system where the db2diag.log
is supposed to be written to? If the disk is full, db2 can't append to the
db2diag.log.


Is there a set of commands that will force db2 to write some
information in the db2diag.log.
Nov 12 '05 #4

P: n/a
In article <d8**************************@posting.google.com >, Ali
Zaidi (sm****@hotmail.com) says...

Is there a set of commands that will force db2 to write some
information in the db2diag.log.


Stop and start the instance
Nov 12 '05 #5

P: n/a
The problem is I don't want to shutdown the DB2 and want the
db2diag.log again become active.

How Can I test to see if nothing write into it? Any harmless command
that add one line to db2diag?

I have enough space is hard, no problem with that.

The db2diag.log is seems freeze with the message I mentioned. i.e.
Warning: active log held by dirty pages.> > > Decrease softmax and/or
increase num_iocleaners

Please advise some solution to reactivate it
sm****@hotmail.com (Ali Zaidi) wrote in message news:<d8**************************@posting.google. com>...
Knut Stolze <st****@de.ibm.com> wrote in message news:<cf**********@fsuj29.rz.uni-jena.de>...
Shawn wrote:
We are on IBM DB2 7.1 ON WINDOWS. The db2diag.log is not working and
no new line written into it for few days. The last lines in
db2diag.log shows:

Warning: active log held by dirty pages.
Decrease softmax and/or increase num_iocleaners.
repeatedly . What is the problem? How can resolve it quickly? The
applicatipna dnLDAP is up and running though.


What's your setting for the DBM CFG parameter named DIAGLEVEL? The default
is 3.

db2 get dbm cfg | more

Also, do you have enough disk space on the file system where the db2diag.log
is supposed to be written to? If the disk is full, db2 can't append to the
db2diag.log.


Is there a set of commands that will force db2 to write some
information in the db2diag.log.

Nov 12 '05 #6

P: n/a
Ian
Shawn wrote:
The problem is I don't want to shutdown the DB2 and want the
db2diag.log again become active.

How Can I test to see if nothing write into it? Any harmless command
that add one line to db2diag?

I have enough space is hard, no problem with that.

The db2diag.log is seems freeze with the message I mentioned. i.e.
Warning: active log held by dirty pages.> > > Decrease softmax and/or
increase num_iocleaners

Please advise some solution to reactivate it


You could:

1) Use LOAD on a table
2) Backup or restore a database
3) Create a situation that generates lock escalation
4) Cause a deadlock

All three can be done without disrupting your application (be careful
if you try #3, though).


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Nov 12 '05 #7

P: n/a
Ian
Shawn wrote:
We are on IBM DB2 7.1 ON WINDOWS. The db2diag.log is not working and
no new line written into it for few days. The last lines in
db2diag.log shows:

Warning: active log held by dirty pages.
Decrease softmax and/or increase num_iocleaners.
repeatedly . What is the problem? How can resolve it quickly? The
applicatipna dnLDAP is up and running though.

Please advise


No news is good news!

If you really think there is a problem, try doing one of the steps I
suggested in a previous note regarding this topic, they will generate
entries in the db2diag.log.

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Nov 12 '05 #8

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