Oracle modifies a row of data memory major changes

Make a request to the Oracle database, modify a row of data, and in memory there are mainly the following changes:

1. The server process reads the block containing the row data into memory

2. Write the redo log. The variable vectors in memory that point to the data block in the undo tablespace are recorded in the Redo log.

3. Copy the data block in memory into the undo segment.

4. Write the Redo log. The change vectors for the specific actions that are modified are recorded to the redo log.

5. Modify the data block.

Redo all changes to the logging database. Each change is recorded at least two times redo log, once used to point to the original mirror block, one time to record the specific changes.

Oracle modifies a row of data memory major changes