Crash Recovery: Big Picture

Start from a checkpoint (found via master record).

Three phases. Need to: Figure out which Xacts committed since checkpoint, which failed (Analysis). REDO all actions. (repeat history) UNDO effects of failed Xacts.

Oldest log rec. of Xact active at crash

Smallest recLSN in dirty page table after Analysis

Last chkpt

CRASH

A

R

U

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