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https://issues.apache.org/jira/browse/TRAFODION-2438?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15832263#comment-15832263
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ASF GitHub Bot commented on TRAFODION-2438:
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GitHub user sureshsubbiah opened a pull request:
https://github.com/apache/incubator-trafodion/pull/922
[TRAFODION-2438] Unnecessary and sometimes wrong delete during upsert…
…/merge with IM
This change is done by Hans. Design by Selva.
Please see JIRA for an explanation.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/sureshsubbiah/incubator-trafodion upsert1
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-trafodion/pull/922.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 #922
----
commit 1450e83627b5bdde6f947c963152ce00f9d5e907
Author: Suresh Subbiah <[email protected]>
Date: 2017-01-20T18:15:06Z
[TRAFODION-2438] Unnecessary and sometimes wrong delete during upsert/merge
with IM
This change is done by Hans. Design by Selva.
Please see JIRA for an explanation.
----
> Missing index rows with UPSERT, executor/test015
> ------------------------------------------------
>
> Key: TRAFODION-2438
> URL: https://issues.apache.org/jira/browse/TRAFODION-2438
> Project: Apache Trafodion
> Issue Type: Bug
> Components: sql-cmp
> Affects Versions: 2.0-incubating
> Reporter: Hans Zeller
> Assignee: Hans Zeller
> Fix For: 2.1-incubating
>
>
> Selva found the cause of this problem and suggested the fix.
> The problem was discovered as a failure of regression test executor/test015,
> with some missing index rows.
> Selva found that this is because we insert a "tombstone" into each alternate
> index for every row, even if it is a new row. Those tombstones for the
> non-existing old rows contain junk or NULL values, and they can potentially
> wipe out existing index rows.
> Selva's suggested fix is to use the "pre-condition" for the index delete to
> check whether an old row actually existed, and only do a delete if it did.
> Here is a simple test case, also from Selva:
> {noformat}
> drop table t015t8 cascade ;
> create table t015t8 (i int not null, j int, k int, primary key(i));
> create unique index t015t8i1 on t015t8(j);
> insert into t015t8 values (4,null,4);
> select * from t015t8;
> -- enable this CQD to try the new, efficient tree
> -- cqd TRAF_UPSERT_TO_EFF_TREE 'on';
> prepare s1 from upsert into t015t8 values (1,2,3),(11,12,13) ;
> execute s1 ;
> set parserflags 1;
> select * from t015t8;
> select * from table (index_table t015t8i1);
> -- wrong answer, 2 rows instead of 3
> {noformat}
> If this does not reproduce the error or if you want to see the extra
> tombstones, do an HBase raw scan to see them:
> {noformat}
> hbase shell
> scan 'TRAFODION.SCH.T015T8I1' , {RAW=>true}
> {noformat}
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