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From selvaganesang <...@git.apache.org>
Subject [GitHub] incubator-trafodion pull request: [TRAFODION-1887] Upsert into ali...
Date Tue, 15 Mar 2016 20:20:22 GMT
Github user selvaganesang commented on a diff in the pull request:

    https://github.com/apache/incubator-trafodion/pull/380#discussion_r56233621
  
    --- Diff: core/sql/optimizer/BindRelExpr.cpp ---
    @@ -10171,17 +10164,26 @@ matched clause of merge). If the upsert caused a row to be updated
in the
     base table then the old version of the row will have to be deleted from 
     indexes, and a new version inserted. Upsert is being transformed to merge
     so that we can delete the old version of an updated row from the index.
    +
    +Upsert is also converted into merge when there are omitted cols with default values and

    +TRAF_UPSERT_WITH_INSERT_DEFAULT_SEMANTICS is set to  OFF in case of aligned format table
or 
    +omitted current timestamp cols in case of non-aligned row format
    --- End diff --
    
    For upsert, in case of non-aligned format, if any column other than the columns with default
current is omitted, the default value is resolved at the time of select. If the current default
column is omitted it will be always changed to merge. User can't force a different behavior
for non-aligned format in this specific case. Rationale here: If we allow user to control
it, then all omitted default columns should always be populated at the time of upsert for
the merge to work correctly.
    
    For non-aligned format, user control it using the above cqd. Default behavior is change
it to merge if the default columns are omitted in upsert.


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