Example of Query Transformation

Consider the query in slide #13:

Filter Query

Monotone Query

m.to = {‘Joe’, ‘Mike’} AND

(m.subject LIKE ‘%CS294-7%’ OR

m.words={‘CS294-7’}) AND

m.ts + [2 weeks] <= now() AND

NOT EXISTS (mreply:

(mreply.sender=‘Joe’ OR

mreply.sender=‘Mike’) AND

mreply.in_reply_to = {m} AND

mreply.ts <= m.ts + [2 weeks]) AND

EXISTS (a: a.type=‘endorsement’ AND

a.msg=m)

Note: the meaning is slightly different from the original one. It returns messages that are not replied by ‘Joe’ or ‘Mike’ within 2 weeks.