Db2 tables altered, reorg

Use this:

db2 +c "lock table tabname in share mode"
db2 +c "alter table tabname add partition <partname> starting 'date' ending 'date' exclusive"
db2 "commit"

Here is the explanation:

+c : disable auto commit, so the command you send will not be committed until an explicit commit command sent or connection closed.

locking table in share mode: means that you want to acquire a shared lock which will prevent other transactions to make changes to the table. So, following command won't be blocked while working.

In this approach you say that: lock the table for me, then issue partition command, while issuing this command other transaction will wait till you finished your job and send commit statement.

I am not sure if it works or not. But it worth a try.

You can only use SQL statements in a trigger. RUNSTATS and REORG are not SQL statements; they are DB2 CLP commands, and only the command line processor understands them. You can try using the system stored procedure ADMIN_CMD() to invoke those utilities, however, 1) it still may not work because of the nature of the utilities and 2) even it does work it would not be a good idea.

There are other problems with your trigger. You cannot use FETCH FIRST in a delete statement, for example. And what is the point of updating statistics just before a REORG?