I am looking as the following article:
I would like to ask about the IMMEDIATE and the DEFERRED part. Sorry I am still confuse and not really understand on it.
in the IMMEDIATE part, it explain that IMMEDIATE is the default, but it requires an instance attachment to be effective. , what does it means that requires an instance attachment to be effective? I though it should be straight take effect after I run the command?
For example:
db2 update dbm cfg using diaglevel 4 immediate
Does this direct take effect on my db2diag log files?
Take care to read the Db2 knowledge-center version that matches your Db2-version. Maybe you are using a more recent version of Db2 like V10.5 or v11.1.
For the DIAGLEVEL parameter, you can change it on the fly i.e. without needing to bounce the Db2-instnce. The new value is effective immediately and you can see this in the db2diag (which will increase quickly in size because of all the extra messages that will appear).
For "instance attachment" it means that you can run db2 attach ... command before running the db2 update dbm cfg ... The details are here.
However, if you are running as the Db2-instance owner and you are on the Db2-server directly (e.g. via ssh etc) then the instance-attachment is not necessary in this specific case. The instance-attachment is necessary when the instance is remote, or is not the current instance, or you are not running as the instance-owner etc.