GitHub user sureshsubbiah opened a pull request:
https://github.com/apache/incubator-trafodion/pull/1056
[TRAFODION 2512] Index access with MDAM not chosen with LIKE predicate
The problem does not show for a query such as
prepare ss1 from select k1 from tbl where b >= '1234567' and b < '12345678';
select k1 from tbl where b like '1234567%';
does get transformed to previous 2 range prepicates, but the histogram is
compressed to one interval for all LIKE predicates. For such simple Like
predicates, it is better to treat the the two range predicates
resulting from LIKE transformation, as any other pair of range predicates.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/sureshsubbiah/incubator-trafodion 2512_a
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/incubator-trafodion/pull/1056.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 #1056
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commit 20ad19a9966c212cb229020d526eb3830f0eb7df
Author: Suresh Subbiah <[email protected]>
Date: 2017-04-10T16:10:50Z
[TRAFODION-2512] index access with MDAM not chosen with LIKE predicicate
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