Guido Moerkotte Thomas Neumann Gabriele Steidl Preventing Bad Plans by Bounding the Impact of Cardinality Estimation Errors. 982-993 2009 2 PVLDB 1 http://www.vldb.org/pvldb/2/vldb09-657.pdf db/journals/pvldb/pvldb2.html#MoerkotteNS09