A report read a salary figure that another transaction had changed but then rolled back, so the report showed a value that never officially existed. What is this called, and which isolation level allows it?
Un rapport a lu un salaire qu'une autre transaction avait modifié puis annulé : le rapport a donc affiché une valeur qui n'a jamais officiellement existé. Comment appelle-t-on cela, et quel niveau d'isolation le permet ?
Answers
AA phantom read, allowed only at the Serializable isolation levelUne lecture fantôme, permise uniquement au niveau Serializable
BA lost update, allowed at every isolation levelUne mise à jour perdue, permise à tous les niveaux d'isolation
CA dirty read, allowed under Read UncommittedUne lecture sale, permise en Read Uncommitted
DA deadlock, allowed under Read CommittedUn interblocage, permis en Read Committed
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