The way how the master replication is working is that whenever you setup the master site of the snapshot, Oracle creates these three replication objects: Master Table, Internal Trigger and a Snapshot Log. The Master table is the base of the snapshot and is located at the target MASTER site. This table can is used for both snapshot replication as well as multimaster replication. The Internal Trigger will be inserting records into a Snapshot Log whenever DML occurs on the Master Table. This is an internal trigger and Oracle takes care of managing it. The Snapshot Log is used when replication uses the FAST REFRESH. It records which rows have been updated/deleted/inserted in the master table, so they could be propagated to the replication sites. So the CHANGE_VECTOR$$ column will be in your master table MLOG$_..... The M_ROW$$ column stored the ROWIDS of rows that have been udpated in the master table. The SNAPTIME$$ column - the last time the records were inserted into the snapshot log. DMLTYPE$$ is for the DML operation occured on the row. And CHANGE_VECTOR$$ is used by the internal trigger. So if you modify its value, you might risk to messed up the replication process.
have been updated/deleted/inserted in the master table, so they could be propagated to the replication sites. So the CHANGE_VECTOR$$ column will be in your master table MLOG$_.....
The M_ROW$$ column stored the ROWIDS of rows that have been udpated in the master table. The SNAPTIME$$ column - the last time the records were inserted into the snapshot log. DMLTYPE$$ is for the DML operation occured on the row. And CHANGE_VECTOR$$ is used by the internal trigger. So if you modify its value, you might risk to messed up the replication process.