In a Research by Infoworld.com.
Oracle has a very fundamental bug which can cause Database crash and cant be recovered
It is the Heart beat of Oracle database, SYSTEM CHANGE NUMBER.
When we Perform Hot backups Generally Oracle server will generate more scn numbers, If it is in a distributed databases When Oracle databases link to each other, maintaining data consistency requires them to synchronize to a common SCN. This is necessarily the highest SCN carried by any participating Oracle database instance because the SCN clock cannot run backward — so database linking causes the SCN in many databases to jump during normal operations. If there are more online backups the scn will jump high form millions to billions in short period, which may cause oracle to stop the instance or even worse database crash.
Oracle has released PATCH for this bug in JAN12 for 11R1 and 11gR2
Please Read Very detailed Article about bug by INFOWORLD.COM
To know More about SCN
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