MaxDB KNLDIAG file access denied

[Former Member]

Hi,

I'm a DBA recently assigned to support MaxDB database (ver 7.6) used by

SAP Content Server in our windows 2003/32 bit environments.

Initially, our windows support group granted the DBA group access to

the files on E:\sapdb\data\wrk\CD1 where the KNLDIAG and other files

are allocated. We were able to view the KNLDIAG file when errors

occurred.

However, when the database instance is placed offine and back online,

we loose access to the KNLDIAG file, but not the other files on the

same directory/subdirectory.

Can you explain what is happening?

Is MaxDB doing something behind the scenes?

What can be done so that we don't loose access to this file?

I would appreciate any help you can provide.

Regards,

Bill

[lbreddemann]

Hi Bill!

> I'm a DBA recently assigned to support MaxDB database (ver 7.6) used by

> SAP Content Server in our windows 2003/32 bit environments.

> Initially, our windows support group granted the DBA group access to

> the files on E:\sapdb\data\wrk\CD1 where the KNLDIAG and other files

> are allocated. We were able to view the KNLDIAG file when errors

> occurred.

> However, when the database instance is placed offine and back online,

> we loose access to the KNLDIAG file, but not the other files on the

> same directory/subdirectory.

>

> Can you explain what is happening?

Yes, no problem!

> Is MaxDB doing something behind the scenes?

Of course not - it's well documented

Unlike Oracle MaxDB does not use the same file all the time to write out the error messages.

Instead, with every restart the last file 'KLNDIAG' (and/or 'KNLMSG' in more recent versions) is renamed to 'KNLDIAG.OLD'. If there is already an 'KNLDIAG.OLD' this file is gone afterwards.

Then a new file is 'KNLDIAG' is created by the MaxDB Kernel with the default permission of the folder.

Usually these are dictated by the Windows account that runs the MaxDB-Service.

If you did not change this, this would be the "local systemaccount".

On my test system this results in default permissions that allow members of "Adminstrators", "Backup Operators", "System" and of course the "Owner/Creator" to access the file.

> What can be done so that we don't loose access to this file?

Simple: if you want to access it via OS tools, make sure that the user is a member of the "Administrators" or the "Backup Operators" group.

If you don't want to do that, just use the file access via the DBMGUI or DB Studio (or DBMCLI) to get access to the file.

regards,

Lars

p.s.

Maybe you didn't notice that by now - the KNLDIAG file is not simply written at the end of the file, but consists of a startup header part and a body which is cyclically overwritten.

For any newbies I cannot overstate the importance of reading the documentation [http://maxdb.sap.com] and/or get a training for it (SAP course ADM 515 really pays of here...)