Monday, November 17, 2008

Oracle - SCNs (system change numbers)

When a transaction is committed as said redo information generated by user process during that transaction is committed to online redo files. But here the issue is when there are several transaction that could occur concurrently or parallel, use same redo log buffer to log information. How does redo log information associated to a specific transaction is identitied?
So when a specific single transaction is committed among those, SCNs which are ID’s that are generated by Oracle for each and every transaction helps to find the associated redo entry for that committed transaction to update online redo log files.

To get SCN number of current transaction we have v$database view:

Select CURRENT_SCN FROM v$option

No comments:

Post a Comment