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Posted to issues@trafodion.apache.org by "Sandhya Sundaresan (JIRA)" <ji...@apache.org> on 2018/02/01 18:39:00 UTC
[jira] [Commented] (TRAFODION-2946) LOB : DTM support needed for
LOB files for DDL and IUD operations
[ https://issues.apache.org/jira/browse/TRAFODION-2946?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16349078#comment-16349078 ]
Sandhya Sundaresan commented on TRAFODION-2946:
-----------------------------------------------
2 concurrent sessions doing DML to a table contianing LOB columns today can cause corruption.
> LOB : DTM support needed for LOB files for DDL and IUD operations
> -----------------------------------------------------------------
>
> Key: TRAFODION-2946
> URL: https://issues.apache.org/jira/browse/TRAFODION-2946
> Project: Apache Trafodion
> Issue Type: New Feature
> Components: dtm
> Affects Versions: any
> Reporter: Sandhya Sundaresan
> Priority: Major
>
> Trafodion DTM needs to recognize LOB HDFS data files that contain the actual critical data for a LOB column and treat them as part of the Trafodion object that contains the LOB column. The Trafodion table itself contains the LOB handle that can be used to derive the LOB data file name/location.
> DDL operations performed on LOB tables today only work on the Trafodion table. The dependent HDFS data files are not treated as part of the DDL transaction. ANy parallel operations or errors during create/drop will leave the table in an inconsistent state.
>
> DML operations on any LOB table only work on the LOB table and it's dependent descriptor tables that are also Trafodion tables (contain offset/length information in the HDFS data file for each LOB column). But the HDFS data file operation is not covered as part of the transaction. So any IUD error will leave the LOB table in an inconsistent state .
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