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https://issues.jboss.org/browse/TEIID-2549?page=com.atlassian.jira.plugin...
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Steven Hawkins resolved TEIID-2549.
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Resolution: Done
enhanced join order scoring to further prevent creating cross joins with unknown costing
information. also updated dependent planning and costing to allow for ndv based upon
table cardinality when no other information is available.
Join planning produces cross joins with limited costing
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Key: TEIID-2549
URL:
https://issues.jboss.org/browse/TEIID-2549
Project: Teiid
Issue Type: Bug
Components: Query Engine
Affects Versions: 7.7
Reporter: Steven Hawkins
Assignee: Steven Hawkins
Fix For: 8.4.1, 8.5
The join planning logic does not gracefully handle a lack of costing information in
effective cross joins (where there is still outside criteria). For example with a small
table x that only has cardinality set and a large table y with no costing information, the
join structure
from x inner join y as y1 on x.col = y1.col inner join y as y2 on x.col1 = y2.col1
can result in a cross join plan between y1 and y2 (although the specifics of the plan may
verify from version to version - in 7.7 the cross join will likely be pushed down, while
in 8.4 a dependent join can be created depending upon the size of x, but can still produce
a pushed cross join).
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