Type: New Feature
Affects Version/s: 0.10.0
Fix Version/s: 0.11
Release Note:This adds a new method, cleanupOnSuccess, to the StoreFunc interface, and thus will cause backward compatibility issues for users who directly implement this interface. Most store functions implement StoreFuncImpl, which will shield them from this issue as it implements the new method.
We are in the process of using PIG for various data processing and component integration. Here is where we feel pig storage funcs lack:
They are not aware if the over all job has succeeded. This creates a problem for storage funcs which needs to "upload" results into another system:
DB, FTP, another file system etc.
I looked at the DBStorage in the piggybank (http://svn.apache.org/viewvc/pig/trunk/contrib/piggybank/java/src/main/java/org/apache/pig/piggybank/storage/DBStorage.java?view=markup) and what I see is essentially a mechanism which for each task does the following:
1. Creates a recordwriter (in this case open connection to db)
2. Open transaction.
3. Writes records into a batch
4. Executes commit or rollback depending if the task was successful.
While this aproach works great on a task level, it does not work at all on a job level.
If certain tasks will succeed but over job will fail, partial records are going to get uploaded into the DB.
Any ideas on the workaround?
Our current workaround is fairly ugly: We created a java wrapper that launches pig jobs and then uploads to DB's once pig's job is successful. While the approach works, it's not really integrated into pig.