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https://reviews.apache.org/r/36895/
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Review request for Ambari, Alejandro Fernandez, Nate Cole, and Sumit Mohanty.
Bugs: AMBARI-12570
https://issues.apache.org/jira/browse/AMBARI-12570
Repository: ambari
Description
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Similar to AMBARI-12526, Ambari installation via a blueprint on SQL Azure gets
stuck somewhere between 90% and 100% because of a SQL Database deadlock.
- We have dual X-locks on hostcomponentstate asking for U-locks when updating
the CLUSTERED INDEX.
- Both dual X-locks, from different transactions and different processes, are
on the same row (technically impossible) - based on the XML execution plan, we
can see that the concurrent UPDATE statements are executing on different rows
due to their CLUSTERED INDEX predicate.
- In Java, Ambari has locks which prevent concurrent U- or X-locks on the same
row
- Only happens on SQL Server
My best suspicion right now is that we have a key hash collision happening on
this table. That's why two processes appear to have the same lock even though
they are on different rows.
Restricting row-level locking on this table will prevent locking on hash keys
which could collide.
Diffs
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ambari-server/src/main/resources/Ambari-DDL-SQLServer-CREATE.sql 0ff1aff
Diff: https://reviews.apache.org/r/36895/diff/
Testing
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Deployed a clean cluster on SQL Server and then ran 10+ deployments on SQL
Azure without seeing a deadlock.
Thanks,
Jonathan Hurley
