Hans Zeller created TRAFODION-2438:
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Summary: 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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