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* R1(X), W2(Y), R3(X)
Reducing conflicts, such as through commutativity, enhances performance because conflicts are the fundamental cause of delays and aborts.
The conflict is '''materialized''' if the requested conflicting operation is actually executed: in many cases a requested/issued conflicting operation by a transaction is delayed and even never executed, typically by a [[Lock (computer science)|lock]] on the operation's object, held by another transaction, or when writing to a transaction's temporary private workspace and materializing, copying to the database itself, upon commit; as long as a requested/issued conflicting operation is not executed upon the database itself, the conflict is '''non-materialized'''; non-materialized conflicts are not represented by an edge in the precedence graph.
====Conflict equivalence====
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