Mload Match TAGs(in DML transaction phase and Application phase) - forum topic by mayya@teradataforum

Hi All,
It is said that in DML transaction phase of mload, "Match tag is assigned to each DML request that will match it with appropriate rows of input data".
what kind of match tags these will be?
And in Application phase, 5 match tags(ImportSEQ,DMLSeq,SMTSeq,ApplySeq,SourceSeq) will be assigned to each row. Then these match tags will be compared with match tags of DML requests which are done in DML transaction phase.
So, please let me know what are the difference between these 2 kinds of match tags?
what are the actual advantages of the match tags and matching each DML request and each data row?
where can i get more information to understand these?