What are Oracle checkpoints?
Purpose of Checkpoints Oracle Database uses checkpoints to achieve the following goals: Reduce the time required for recovery in case of an instance or media failure. Ensure that dirty buffers in the buffer cache are written to disk regularly. Ensure that all committed data is written to disk during a consistent …
What is Oracle incremental checkpoint?
“An incremental checkpoint is a type of thread checkpoint partly intended to avoid writing large numbers of blocks at online redo log switches. DBWR checks at least every three seconds to determine whether it has work to do.
What is the difference between Pmon and Smon?
PMON and SMON are two required background processes. PMON is the Process Monitor which is responsible for recovering processes when the user process fails. PMON does the process cleanup. SMON is the System Monitor which is responsible for recovering the system after a failure.
How does Flink checkpoint work?
A checkpoint in Flink is a global, asynchronous snapshot of application state that’s taken on a regular interval and sent to durable storage (usually, a distributed file system). In the event of a failure, Flink restarts an application using the most recently completed checkpoint as a starting point.
What is instance recovery in Oracle?
Instance recovery refers to the case where a surviving instance recovers a failed instance in an Oracle Real Application Clusters database. The goal of crash and instance recovery is to restore the data block changes located in the cache of the dead instance and to close the redo thread that was left open.
Where are Oracle restore points?
You can also use the following query to view only the guaranteed restore points: SQL> SELECT NAME, SCN, TIME, DATABASE_INCARNATION#, GUARANTEE_FLASHBACK_DATABASE, STORAGE_SIZE FROM V$RESTORE_POINT WHERE GUARANTEE_FLASHBACK_DATABASE=’YES’; For normal restore points, STORAGE_SIZE is zero.
What is the difference between savepoint and checkpoint?
Checkpoints are taken automatically and are used for automatic restarting job in case of a failure. Savepoints on the other hand are taken manually, are always stored externally and are used for starting a “new” job with previous internal state in case of e.g. A/B testing, etc.
What is stored in Flink checkpoint?
Directory Structure. Similarly to savepoints, a checkpoint consists of a meta data file and, depending on the state backend, some additional data files. The meta data file and data files are stored in the directory that is configured via state. checkpoints.