Locking with onutil CHECK Options

The database server places a shared lock on tables when the onutil CHECK command checks system catalog tables or when you execute the onutil CHECK INDEX WITH DATA command. The database places a shared-intent lock for onutil CHECK options that check table data or indexes. A shared-intent lock allows other users to select, insert, update and delete rows, but no user can delete the table during the locking operation.

Because data modification can occur with a shared-intent lock, onutil must distinguish between real corruption and temporary data inconsistencies. (An example of a temporary data inconsistency is the ever-changing structure of a B-tree index.) The onutil CHECK utility uses time stamps to find data inconsistencies. If onutil CHECK reports an inconsistency while it checks a database table or index, it is recommended that you rerun the onutil CHECK command with the LOCK option. The LOCK option places a share lock on the table while the check is performed. Then, if the onutil CHECK...LOCK command reports data inconsistency, repair the data.