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https://issues.apache.org/jira/browse/TRAFODION-1848?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15179433#comment-15179433
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Sandhya Sundaresan commented on TRAFODION-1848:
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Changes have been made to perform GC as part of an insert or update operation.
As a further improvement we should probably add a utility operation that does
GC in an offline mode. For now, GC kicks in during an insert/update or append,
when the lob data file has reached a certain threshold. The threshold is
controllable via a CQD.
All functionality has moved into the master executor process including the new
GC function. The infrastructure to launch and send messages to the mxlobsrvr
process from the master is still retained but no message is actually sent to it
now. We may use it in the future for other functions and may even move GC to
that process. The mxlobsrvr executable will still be built but it will not be
launched as part of process startup since it is not needed right now.
As part of moving this functionality also refactored some of the code.
> LOB infrastructure changes to support GC and get rid of unneeded mxlobsrvr
> process
> ----------------------------------------------------------------------------------
>
> Key: TRAFODION-1848
> URL: https://issues.apache.org/jira/browse/TRAFODION-1848
> Project: Apache Trafodion
> Issue Type: Improvement
> Components: sql-exe
> Affects Versions: any
> Reporter: Sandhya Sundaresan
> Assignee: Sandhya Sundaresan
> Fix For: 2.0-incubating
>
> Original Estimate: 672h
> Remaining Estimate: 672h
>
> Need support to compact lob data files after a certain threshold is reached .
> Deleting or updating a table with lob columns cn cause the lob datafiles to
> be left with unused holes. These need to be compacted regularly.
> TO simplify the flow of execution, the mxlobsrvr process functionality is
> being moved into the master executor. There is no need for a spearate process
> anymore since there isn't going to be a separate storage engine that may need
> to make calls to this process. The lob file processing can all be done in
> the master process itself.
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