CDR check replicate & locking

11.50.FC8 AIX 5.2 ER bi-directional between two instances. We have a production instance where a handfull of our replicates became out of sync. Since this is a 24x 7 env, need to know what kind of locking cdr check uses .. will running cdr check/repair on the affected replicates cause users/applications to encounter locking errors on those tables ; if there are locks held will the lock be held be just for the duration the row is checked ? All repls tables do have a crcols defined but are not part of replicate sets. Thanks, Mark