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Oracle Tips by Burleson |
Oracle 10g Transaction Manageability
The user can roll back Oracle database
transactions with the ROLLBACK statement and also during instance
recovery by the Oracle database. When the system crashes and
instance recovery begins, the SMON process scans all the
rollback/Undo segments and recovers the unfinished transactions.
In the case of instance recovery, if the
unfinished transactions are large enough, the SMON process spawns
parallel transaction recovery servers to recover. Prior to Oracle
Database 10g, you could monitor the parallel transaction recovery
with two views: v$fast_start_servers and v$fast_start_transactions.
However, you could not monitor normal
transaction rollback or transactions recovered by SMON. With the
changes introduced in Oracle Database 10g, it is possible to view
and monitor the real-time normal transaction rollback and
transaction recovery with the SMON process.
Now, you can even view the historical
information about the transaction recovery and also work out the
average rollback duration. With the current state of the recovery,
you can find out how much work has been done and how much work
remains. Thus, it becomes possible to estimate transaction recovery
time and set the fast_start_parallel_rollback parameter suitably to
optimize the system performance.
Get the complete Oracle10g story:
To get the code instantly, click here:
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