|< < 11 > >|

Strict Two-Phase Locking

Lock compatibility

shared exclusive
shared X
exclusive X X

  • X: Locks are incompatible.

  • Read an item after obtaining a shared lock on it.

  • Write an item after obtaining an exclusive lock on it.

  • Any number of transactions can read an item at the same time.

  • At most one transaction can write an item at any time.

|< < 11 > >|