tx-logging vs. redundancy for databases

Chris Muller afunkyobject at yahoo.com
Fri May 14 02:13:36 UTC 2004

> When the memory content was lost, Oracle replays the redo log entires
> that have a larger system change number (SCN) than the database
> files. This is done in two phases: first ALL changes are applied (roll
> forward) and then transactions that lack a commit are undone (roll
> back) in the usual way using rollback segments..

When memory was lost, why does it bother to apply any of the changes without a
commit in the first place?  Couldn't it just skip them entirely and only apply
those that were written wholly?

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