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https://issues.apache.org/jira/browse/TRAFODION-1914?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15289076#comment-15289076
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liu ming commented on TRAFODION-1914:
-------------------------------------
>>create table ut1 ( c1 int not null, c2 int not null, primary key (c1) );
--- SQL operation complete.
>>insert into ut1 Values(1,1);
--- 1 row(s) inserted.
>>create unique index ui1 on ut1(c2);
--- SQL operation complete.
>>exit
then use hbase shell
hbase(main):002:0> scan 'TRAFODION.SEABASE.UI1'
ROW COLUMN+CELL
\x80\x00\x00\x01 column=#1:\x01,
timestamp=1463582407513,
value=\x08\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x01\x00\x00\x00
1 row(s) in 0.0800 seconds
> optimize "added columns" in indexes
> -----------------------------------
>
> Key: TRAFODION-1914
> URL: https://issues.apache.org/jira/browse/TRAFODION-1914
> Project: Apache Trafodion
> Issue Type: Improvement
> Components: sql-cmp
> Reporter: Eric Owhadi
>
> the current CREATE INDEX feature will always put each column added to the
> index in the clustering key. But sometimes, users just want to add columns to
> the index to avoid having to probe back the primary table to fetch just one
> or 2 column back. Instead copying these columns in the index can avoid making
> a probe back to main table and therefore improve performance. Current
> implementation allows this, but will always put the extra column as part of
> the clustering key. That is not optimal, and very bad for the case of
> VARCHAR, since they are exploded to there max size when part of the
> clustering key. So this JIRA is abount altering the syntax of create index,
> and flag columns that are added but should not be part of the clustering key.
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