When you do not specify the SPOOL, TEMPORARY, or PERM options, MODIFY USER places an ACCESS lock on the database being altered to run concurrently with all DML requests.
Specifying the SPOOL, TEMPORARY, and PERM options require an EXCLUSIVE lock.
This statement also places a rowhash WRITE lock on the database for DBC.DBase. The SPOOL, TEMPORARY, and PERM options then place a second lock on the immediate parent for DBC.DBase. For PERM, the second lock is a rowhash-level WRITE lock. For SPOOL or TEMPORARY, the second lock is a rowhash-level READ lock.
The SPOOL, TEMPORARY, and PERM options also place a rowhash-level WRITE lock on DBC.DataBaseSpace. The PERM option then places a second rowhash-level WRITE lock on the immediate parent for DBC.DataBaseSpace.