TECH TIP: What the rollback dafafile is for?

Document created by Yulun.Zhang Employee on Oct 7, 2014Last modified by Yulun.Zhang Employee on Dec 17, 2016
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Rollback datafile is used to hold any undo or uncommitted data of a particular transaction or a set of transactions. Thus a sudden increase in size for rollback datafile normally means that there are more update sql or a long running update sql are running, that include any sql on insert, update and delete. Sometimes a snapshot too old with ora-1555 may appear when the rollback segment is short of space.