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https://issues.apache.org/jira/browse/TRAFODION-1435?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15505119#comment-15505119
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ASF GitHub Bot commented on TRAFODION-1435:
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GitHub user sbroeder opened a pull request:
https://github.com/apache/incubator-trafodion/pull/712
Second set of changes for JIRA [TRAFODION-1435]
Region operations performed transactionally for delete, chackAndDelete
Improved endpoint coprocessor exception logging
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/sbroeder/incubator-trafodion sean_traf
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-trafodion/pull/712.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #712
----
commit ac28331a6b6e7fc08f07a377b673a420e4d7f099
Author: Sean Broeder <sbroeder@edev06.esgyn.local>
Date: 2016-09-20T00:11:49Z
Second set of changes for JIRA [TRAFODION-1435]
Region operations performed transactionally for delete, chackAndDelete
Improved endpoint coprocessor exception logging
----
> SQL operations not always performed transactionally with AUTOCOMMIT OFF
> -----------------------------------------------------------------------
>
> Key: TRAFODION-1435
> URL: https://issues.apache.org/jira/browse/TRAFODION-1435
> Project: Apache Trafodion
> Issue Type: Improvement
> Components: dtm
> Affects Versions: 0.6 (pre-incubation)
> Reporter: Sean Broeder
> Assignee: Sean Broeder
> Original Estimate: 672h
> Remaining Estimate: 672h
>
> For single region, single row operations (both IDU DML as well as select) SQL
> will avoid beginning a transaction and perform the operation directly in
> HBase.
> The feeling was that for single row operations a trasnaction was not
> necessary as HBase would make the operation atomic and provide the necessary
> guarantees. The problem is this circumvents the endpoint coprocessor and
> makes conflict detection with other concurrent transactions impossible.
> For performance reasons we should try to approximate the autocommit behavior
> as much as possible while preserving the conflict detection. We can achieve
> this by implementing 'region transactions' whereby the region will create its
> own transaction identifier when a nontransactional operation arrives in the
> coprocessor. We will need to override all HTable nontransactional operations
> in both the TransactionalTable and SsccTransactionalTable classes. The
> override will create a new transaction identifier specific to the region
> transaction and then use that for all modifications as if it were issued by
> the DTM.
> The transaction identifier needs to be unique so that other threads
> performing similar operations do not get confused at conflict resolution
> time. One possibility is to maintain an AtomicLong in the region that can be
> incremented whenever such a transaction is needed. This keeps all processing
> inside the region and eliminates any RPC to another server process.
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