Let's say you can go back in time and run a query over and over again. Let's also assume that there are many other concurrent DML on the tables *while* the query is executing. Do you want your query result to be
1) the same , everytime
2) anything, depends on what is happening to the rows.
??
I prefer option#1.
It is important to note at this point that none of the isolation level in DB2 , (RR, RS, CS, UR) can give you option#1. RR, RS, and CS would only prevent modifications *after* those matching rows have been fetched. So, it is still possible to modify some rows that are supposed to match the criteria of the query *before* they are fetched, and that may mean the query result can differ from run to run.
Sounds fun? ;)
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