Commit Process
Oracle generates a revocation record in the SGA undo segment buffer. The revocation record contains the old values for updating and deleting table rows.
Oracle generates redo log records in the SGA redo log Buffer
Modify the buffer in the SGA database in Oracle
- When a commit is submitted
The transaction in the redo record is marked as the unique SCN log of the committed transaction. The program will redo the transaction log information and the transaction SCN, release the Oracle lock from the redo log file written from the redo log buffer to the disk and mark the transaction as completed
Commit Parameters
Commit_wait initialization parameter commit_wait = {Nowait | wait | force_wait} Oracle uses the commit method by default as the wait function: controls the write mode of redo logs. Remarks: Nowait applicable scenarios (A, there are a large number of transaction redo, information needs to be written into the redo log; B, to tolerate part of the data loss; C, waiting for lgwr to write can not be tolerated by the application ). Force_wait: Oracle will be applied by default to submit commit_logging initialization parameter commit_logging = {immediat | batch} immediat: lgwr to write redo information to the redo log file immediately batch: The redo information will be buffer, that is, redo logs are not immediately written to the redo log file.
Commit usageCommit commit write wait; Commit write Nowait commit write batch; Commit write immediate; wait and Nowait control when redo information is written to redo logsimmediat and batch control how redo information is written to redo logs. Remarks: PL/SQL default batch Nowait
