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From DaveBirdsall <...@git.apache.org>
Subject [GitHub] incubator-trafodion pull request #1044: [TRAFODION-2575] Truncate long strin...
Date Tue, 04 Apr 2017 21:19:13 GMT
GitHub user DaveBirdsall opened a pull request:

    https://github.com/apache/incubator-trafodion/pull/1044

    [TRAFODION-2575] Truncate long strings when computing USTAT aggregates

    This change affects the SELECTs that UPDATE STATISTICS generates when computing aggregates
on long character and varchar columns. We now truncate the string before doing aggregation.
(Note: We already do this in other code paths in UPDATE STATISTICS -- namely internal sorts
and sample table population. This particular code path was overlooked.)
    
    Besides improving performance, this will avoid UPDATE STATISTICS failing due to lingering
engine issues concerning long varchars and sorts.

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/DaveBirdsall/incubator-trafodion Trafodion2575

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/incubator-trafodion/pull/1044.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #1044
    
----
commit ca7c9c589eb01497ed7b24a83da812a75361999f
Author: Dave Birdsall <dbirdsall@apache.org>
Date:   2017-04-04T21:14:47Z

    [TRAFODION-2575] Truncate long strings when computing USTAT aggregates

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