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Ship it! Ship It! - Nate Cole On July 29, 2015, 9:11 p.m., Jonathan Hurley wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/36895/ > ----------------------------------------------------------- > > (Updated July 29, 2015, 9:11 p.m.) > > > 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 > ------- > > 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 > ----- > > ambari-server/src/main/resources/Ambari-DDL-SQLServer-CREATE.sql 0ff1aff > > Diff: https://reviews.apache.org/r/36895/diff/ > > > Testing > ------- > > Deployed a clean cluster on SQL Server and then ran 10+ deployments on SQL > Azure without seeing a deadlock. > > > Thanks, > > Jonathan Hurley > >
