aborted read

intermediate read

a transaction reads a version from the middle of another transaction rather than its final committed write (G1b)

cyclic information flow

transactions observe or overwrite each other's writes in a cyclic pattern (G1c)

garbage read

a database returns an object version not produced by any write, often from corruption or race conditions

lost update

a committed transaction's effects are lost due to another transaction's concurrent write to the same object (P4)

dirty read

one transaction reads data written by another before that transaction has completed (P1)

non-repeatable read

a transaction modifies data that another ongoing transaction previously read (P2)