I read some where some time ago that regardless of the transaction size, meaning more steps in a transactions vs fewer, the time to commit is the same. Why so? Thanks.
Printable View
I read some where some time ago that regardless of the transaction size, meaning more steps in a transactions vs fewer, the time to commit is the same. Why so? Thanks.
This is not exactly true.
There will be a difference in time taken for the two cases however the difference may be small enough for you to notice.
Here is what happens when a COMMIT is issued --
=============
The internal transaction table for the associated rollback segment records that the transaction has committed, and the corresponding unique system change number (SCN) of the transaction is assigned and recorded in the table.
The log writer process (LGWR) writes redo log entries in the SGA's redo log buffers to the online redo log file; it also writes the transaction's SCN to the online redo log file. This atomic event constitutes the commit of the transaction.
Oracle releases locks held on rows and tables. (See "Locking Mechanisms" for a discussion of locks.)
Oracle marks the transaction "complete".
=============
The second step (about Log writer writing entries from Redo buffer to the redo files on disk) may take less or more time depending upon how much is there in the buffer to be written which will be derived from what your transaction was doing; It's not necessarily the number of steps in the transaction but the amount of redo buffers generated due to that.
- Rajeev