UDB V8.2
OS : AIX

I have got this particular query ,,which is failing with deadlock error.
"delete from xxxy where policeis null and logon not in (select logon from emp"

DB21034E The command was processed as an SQL statement because it was not a
valid Command Line Processor command. During SQL processing it returned:
SQL0911N The current transaction has been rolled back because of a deadlock
or timeout. Reason code "2". SQLSTATE=40001

there is no other thred which is using this particular table.
I see other statements with the same table name but a different table name in subselect is executing.

what could be the reason for failure?

get snapshot for locks while you run this statement..it explains who is waiting , who is locking
db2 'reset monitor all'
db2 'update monitor switches .....'
db2 'get snapshor for locks on dbname'

Concert the query and sub-query to where not exists (select ...