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https://issues.apache.org/jira/browse/OOZIE-2854?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andras Piros updated OOZIE-2854:
--------------------------------
Attachment: OOZIE-2854.006.patch
All functionalities covered here. A blacklist based
{{javax.persistence.PersistenceException}} retry predicate is present to
provide a database agnostic method to identify which {{Exception}} instances
originating from JPA / DBCP / JDBC layers are good candidates to begin /
continue retrying.
Tests covered:
* unit tests
** testing the retry handler, the retry predicate filter, and parallel calls to
JPA {{EntityManager}} (mostly Oozie database reads and writes) when injecting
failures
* integration tests
** using the {{MiniOozieTestCase}} framework
** fixing it so that also asynchronous workflow applications (the ones that use
{{CallableQueueService}}) can be run
** for following workflow scenarios:
*** a very simple one consisting only of a {{<start/>}} and an {{<end/>}} node
*** a more sophisticated one consisting of multiple synchronous {{<fs/>}} nodes
and a {{<decision/>}} node
*** the ultimate one consisting of a {{<decision/>}} node, and two branches of
an {{<fs/>}} and an asynchronous {{<shell/>}} nodes
Test cases run:
{noformat}
mvn clean test
-Dtest=TestDBOperationRetryHandler,TestPersistenceExceptionSubclassFilterRetryPredicate,TestParallelJPAOperationRetries,TestWorkflow,TestWorkflowRetries,TestJPAService
{noformat}
> Oozie should handle transient database problems
> -----------------------------------------------
>
> Key: OOZIE-2854
> URL: https://issues.apache.org/jira/browse/OOZIE-2854
> Project: Oozie
> Issue Type: Improvement
> Components: core
> Reporter: Peter Bacsko
> Assignee: Andras Piros
> Attachments: OOZIE-2854-001.patch, OOZIE-2854-002.patch,
> OOZIE-2854-003.patch, OOZIE-2854-004.patch, OOZIE-2854-005.patch,
> OOZIE-2854.006.patch, OOZIE-2854-POC-001.patch
>
>
> There can be problems when Oozie cannot update the database properly.
> Recently, we have experienced erratic behavior with two setups:
> * MySQL with the Galera cluster manager. Galera uses cluster-wide optimistic
> locking which might cause a transaction to rollback if there are two or more
> parallel transaction running and one of them cannot complete because of a
> conflict.
> * MySQL with Percona XtraDB Cluster. If one of the MySQL instances is killed,
> Oozie might get "Communications link failure" exception during the failover.
> The problem is that failed DB transactions later might cause a workflow
> (which are started/re-started by RecoveryService) to get stuck. It's not
> clear to us how this happens but it has to do with the fact that certain DB
> updates are not executed.
> The solution is to use some sort of retry logic with exponential backoff if
> the DB update fails. We could start with a 100ms wait time which is doubled
> at every retry. The operation can be considered a failure if it still fails
> after 10 attempts. These values could be configurable. We should discuss
> initial values in the scope of this JIRA.
> Note that this solution is to handle *transient* failures. If the DB is down
> for a longer period of time, we have to accept that the internal state of
> Oozie is corrupted.
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