5.9 Phantoms

• Problems when using 2PL with inserts and deletes

T1: Read Accounts 1, 2, and 3

T2: Insert Accounts[4, Tacoma, 100]

T2: Read Assets(Tacoma), returns 500

T2: Write Assets(Tacoma, 600)

T1: Read Assets(Tacoma), returns 600

T1: Commit

Accounts Assets

The phantom record

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