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https://issues.apache.org/jira/browse/TRAFODION-2946?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16496935#comment-16496935
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ASF GitHub Bot commented on TRAFODION-2946:
-------------------------------------------
Github user sandhyasun commented on a diff in the pull request:
https://github.com/apache/trafodion/pull/1586#discussion_r192186819
--- Diff: core/sql/generator/GenPreCode.cpp ---
@@ -4520,7 +4520,9 @@ RelExpr * GenericUpdate::preCodeGen(Generator *
generator,
{
oltOptInfo().setOltOpt(FALSE);
generator->oltOptInfo()->setOltOpt(FALSE);
- generator->setAqrEnabled(FALSE);
+ //enabling AQR to take care of the lock conflict error 8558 that
+ // should be retried.
+ // generator->setAqrEnabled(FALSE);
--- End diff --
The while insert would get retried again. The insert/select operation of
lob columns treats the input to the target table as a char string and does it
in chunks. If there is lock clash, the transaction gets aborted and we retry.
> LOB : Locking/transaction 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, sql-general
> Affects Versions: any
> Reporter: Sandhya Sundaresan
> Assignee: Sandhya Sundaresan
> Priority: Major
> Attachments: Locking issue for concurrent access of LOBs.docx
>
>
> 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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