MySQL Online Backup

My summary of the MySQL Online Backup algorithm.

There are basically 2 backup methods:

• "At end" - Point Behind method
• "At begin" - Point Forward method, this is also know as a snapshot backup.
  

1. INITIAL PHASE
   
   • "At end" - Scan and write all data, and at the same time,
   • start writing all changes to a log.
2. READY TO CREATE A VALIDITY POINT
   The engine is ready to create a validity point instantly.
   
   • "At end" - All data has been scanned, continue to write changes to a log.
3. WAITING PHASE
   The engine is waiting for all other engines to reach the waiting phase.
   
   • "At end" - Continue to write changes to log.
4. CREATE VALIDITY POINT
   The engine creates the validity point quickly.
   Changes after this point do NOT belong in the backup.
   
   • "At end" - Stop logging changes.
   • "At begin" - Create snapshot now!
5. FINAL PHASE
   
   • "At end" - Write all changes recorded in the log.
   • "At begin" - Write all data in the snapshot.
6. BACKUP END
   All engines have finished the final stage.