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David Wayne Birdsall commented on TRAFODION-2661: ------------------------------------------------- See also JIRA TRAFODION-1641. > MDAM not chosen for OR predicate of leading index column > -------------------------------------------------------- > > Key: TRAFODION-2661 > URL: https://issues.apache.org/jira/browse/TRAFODION-2661 > Project: Apache Trafodion > Issue Type: Bug > Components: sql-cmp > Affects Versions: 2.0-incubating > Reporter: Hans Zeller > Assignee: David Wayne Birdsall > > We saw the following issue in a customer scenario: > SELECT SUM(c) > from tbl2 > where a in ('A','B') > AND b >= '8'; > The table has a salted index on column a. That index has many more columns > (13 in this case, including the salt column). > The plan we would expect is an MDAM plan with no predicate on _SALT_ and the > OR predicate on column a. > However, we get a full index scan (we can use an index-only scan in this > case). > When we force an MDAM plan, we see a vastly higher cost (250,000 in our > example) than for the single subset plan (cost of 9 in our example). > Dave has already mentioned that this has to do with RangeSpecs. The following > workaround gives the MDAM plan for us: > cqd RANGESPEC_TRANSFORMATION 'off'; -- This message was sent by Atlassian JIRA (v6.4.14#64029)