(2008) Point-In-Time Recovery for Hadoop
- SNP
Analytics
The PIT recovery feature allows to make the state of a system consistent. This functionality allows to synchronize the Hadoop with the primary database. Perhaps the primary database has been rolled back to a certain moment and the archive is now in an inconsistent state with the primary database. This functionality analyzes the situation and chooses a timestamp to perform the rollback on an archive.
Before you can start to use these functionalities, you should enable Point-In-Time Recovery (PIT) in DataTiering Settings Tab.
Using the Task Editor
To synchronize the Hadoop with the primary database:
- Launch transaction /DVD/TH_EDIT, open the process /DVD/SM_CHL_CONS and hit F8.
- Create a new task with a new Run ID by clicking the button below (or by hitting F8 key).
- Name your Run ID.
- Now you are ready to run your PIT tasks.
If you look at the task hierarchy on the screen, you will see that the PIT recovery process contains 6 different subtasks divided in 2 groups:
- Analysis: This optional subtask analyzes what operations are required to make the archive consistent with the primary database.
- Execution: This subtask performs operations to make the archive consistent with the primary database.
For each subgroup there are three operations:
- Generate the analysis / synchronization tasks: You can insert the DataProviders you are testing as a parameter here and then execute a report which generates a task for each DataProvider.
- Analyze the DataProviders / Execute the synchronization process: Executes either the analysis tasks or the synchronization tasks that were previously generated on the DataProviders.
- Show the results of the analysis / synchronization: Displays a report detailing the operations that are completed on each DataProvider.
To delete data used for PIT recovery older than a certain timestamp, use report /DVD/SM_CHL_DELETE. The idea is schedule the execution of this job periodically to avoid growth of the database.
To clean the details of these tasks there is the report /DVD/SM_CHL_CLEAN_TASK which takes as input a set of Run IDs and cleans all information about them.
If for some reason you want to re-open and existing Run ID you can do it via transaction /DVD/TH_MONITOR and entering your Run ID (in our example "PIT_RUN") in the Task run ID field.