Save point in SAP HANA

 

1.What are savepoints?

• Savepoints are required to synchronize changes in memory with the persistency on disk level. All modified pages of row and column store are written to disk during a savepoint.


• Each SAP HANA host and service has its own savepoints.


• The data belonging to a savepoint represents a consistent state of the data on disk and remains untouched until the next savepoint operation has been completed.

 

2.When is a savepoint triggered?

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  Savepoint interval(automatic)

  
  During normal operations, savepoints are automatically triggered when a predefined time since the last savepoint is passed. The length of the time interval between two consecutive savepoints can be controlled with the following parameter:
  
  global.ini -> [persistence] -> savepoint_interval_s
  
  Its default value is 300, so savepoints are taken at intervals of 300 seconds (5 minutes).


• 
  

  System command (manual)

  
  The following command can be used to execute a savepoint manually:
  
  ALTER SYSTEM SAVEPOINT


• 
  

  Soft shutdown

  
  A soft shutdown invokes a savepoint before the services are stopped.
  
  A hard shutdown doesn't trigger a savepoint. This can increase the subsequent restart time.


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  Backup

  
  A global savepoint is performed before a data backup is started.
  
  A savepoint is written after the backup of a specific service if finished.


• 
  

  Startup

  
  After a consistent database state is reached during startup, a savepoint is performed.


• 
  

  Snapshots

  
  Snapshots are savepoints that are preserved for longer use and so they are not overwritten by the next savepoint.