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Recovery Algorithm

  

ARIES recovers from a system crash in three phases.

 

a) Analysis Pass: This pass determines which transactions to undo, which pages were dirty at the time of the crash, and the LSN from which the redo pass should start.

 

b) Redo Pass: This pass starts from a position determined during analysis, and performs a redo, repeating history, to bring the database to a state it was in before the crash.

 

c) Undo Pass: This pass rolls back all transactions that were incomplete at the time of the crash.

 

Reference Link

Recovery Algorithm