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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/34821/
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(Updated May 29, 2015, 8:06 p.m.)


Review request for Ambari, Robert Nettleton, Sumit Mohanty, Sid Wagle, and Tom 
Beerbower.


Bugs: AMBARI-11542
    https://issues.apache.org/jira/browse/AMBARI-11542


Repository: ambari


Description
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When provisioning a cluster via the blueprint api, occasionally a database 
deadlock is detected. There is retry logic around this code so it doesn't 
affect the creation of the cluster and a user wouldn't notice this unless they 
looked at the logs. That being said, this issue involves incorrect transaction 
demarcation and synchronization and is potentially serious depending on how it 
is manifested.

The fix involves changing the scope of the database transaction as well as 
synchronization.
There are currently many issues transaction/synchronization issues in the state 
layer that need to be addresses, this only deals with this exact use case.

Also, this patch strictly deals with correctness and I didn't make an effort to 
optimize this path.  If this results is a performance regression, there are 
several approaches that we could take.


Diffs
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ambari-server/src/main/java/org/apache/ambari/server/controller/AmbariManagementControllerImpl.java
 792b6fe 

Diff: https://reviews.apache.org/r/34821/diff/


Testing (updated)
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Provison clusters many times via looking for a reported database deadlock.  
Without this patch, I was able to reproduce the deadlock fairly consistently 
and with the patch no deadlock occurred across many installs.

Unit Tests:
- tx/synchronization change only so no new unit test
- currently running full unit test suite and will update review with result 
summary when completed


Results :

Tests run: 3020, Failures: 0, Errors: 0, Skipped: 21
...
Total run:744
Total errors:0
Total failures:0


Thanks,

John Speidel

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