[jira] [Commented] (TRAFODION-2755) Create *Trafodion SQL Large Objects Guide* 2

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TRAFODION-2755?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16190464#comment-16190464 ] 

ASF GitHub Bot commented on TRAFODION-2755:
-------------------------------------------

Github user DaveBirdsall commented on a diff in the pull request:

    https://github.com/apache/incubator-trafodion/pull/1247#discussion_r142537556
  
    --- Diff: docs/lob_guide/src/asciidoc/_chapters/working_with_lob.adoc ---
    @@ -751,4 +751,380 @@ CQD `LOB_MAX_SIZE` (default 10G expressed in M [10000M]).
     
     * Extract Target Locations
     +
    -The file to extract to can be a local linux file or a local HDFS file.
    \ No newline at end of file
    +The file to extract to can be a local linux file or a local HDFS file.
    +
    +[#deleting column from a sql table containing lob columns]
    +== Deleting Column from a SQL Table Containing LOB columns
    +
    +[#syntax]
    +=== Syntax
    +
    +```
    +DELETE lob-column-name FROM table-name [WHERE CLAUSE]
    +```
    +
    +[#considerations]
    +=== Considerations
    +
    +When one or more rows containing LOB columns are deleted from LOB table, only the metadata information is dropped and the hdfs data remains as it is. The references to the lob data are removed from the lob descriptor file. 
    +
    +This mechanism has not been implemented yet as a separate utility but it is triggered as a part of insert, update and append operations. For more information, see <<garbage collection,Garbage Collection>>.
    +
    +[#dropping a sql table containing lob columns ]
    +== Dropping a SQL Table Containing LOB Columns 
    +
    +Drop works like any other drop table. All dependent tables are deleted. All files in hdfs (data and descriptor) files are also deleted.
    +
    +For more information, see <<drop_table_statement,DROP TABLE Statement>> in http://trafodion.incubator.apache.org/docs/sql_reference/index.html[Trafodion SQL Reference Manual].
    +
    +[#garbage collection]
    +== Garbage Collection
    +
    +When a lob datafile for a column has reached a certain limit, defined by a CQD `LOB_GC_LIMIT_SIZE`, then a compaction is triggered automatically. +
    +The default GC Limit is 10GB and can be changed if needed. 
    --- End diff --
    
    Should define the GC acronym. For example, "The default Garbage Collection (GC) limit is ..." Then you can use GC later when you mean Garbage Collection.


> Create *Trafodion SQL Large Objects Guide* 2
> --------------------------------------------
>
>                 Key: TRAFODION-2755
>                 URL: https://issues.apache.org/jira/browse/TRAFODION-2755
>             Project: Apache Trafodion
>          Issue Type: Documentation
>            Reporter: Liu Yu
>            Assignee: Liu Yu
>




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