monitor and control executions of long query

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"OLAP and DSS  very frequently use the applications that include SQL queries running over the long period of times.At the moment, the existing database systems provide no control over the execution of long queries.so can we implementation of query processing system that allows a user to monitor and to control execution of the long queries."(background)

who can help me to give me some idea of the questions  of this topic:
1.why the query processing system are unable to monitor execution of long queries?
Upon this quesion,in my opinion beacuse the database systems are like black boxes: You give them input, they compute  for a long time, and then they give the accurate output.but i think it is not the key to this question.is it right??any suggestion for this question??

2.At present, are there some monitoring techniques for the long running query?
I try to find some,but actually they are all monitoring techniques for the database not the query. Would someone give me some clud??
thank you very much

thank u