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https://issues.apache.org/jira/browse/TRAFODION-40?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hans Zeller resolved TRAFODION-40.
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Resolution: Implemented
Fix Version/s: 2.0-incubating
Code was merged in https://github.com/apache/incubator-trafodion/pull/34
> Compiler work to allow a conditional delete
> -------------------------------------------
>
> Key: TRAFODION-40
> URL: https://issues.apache.org/jira/browse/TRAFODION-40
> Project: Apache Trafodion
> Issue Type: Sub-task
> Reporter: Hans Zeller
> Fix For: 2.0-incubating
>
>
> Part of TRAFODION-14.
> Selva and Suresh found that we sometimes miss index rows. This is causes if
> all of the following happen: a) we perform index maintenance for an update
> (delete of the old index row, followed by insert of the new row), b) the old
> and new row of the index have the same row key, i.e. we didn't change the
> column values in the index and c) the HBase timestamp is the same for the
> index delete and the update (delete and insert happen in the same
> millisecond).
> Selva suggested to solutions:
> 1. Determine the max. timestamp of the old row and use that timestamp for the
> delete. That would work (unlikely someone did an insert in a different
> statement in the same millisecond), but it would require reading the value
> before an index delete.
> 2. Add a new expression for the index delete (could also do it for the
> insert) that skips the delete if old and new index values match.
> We want to go with solution 2., since it has the better performance. I'm
> filing this JIRA for the necessary compiler work,
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