[teiid-issues] [JBoss JIRA] (TEIID-1990) UNION pushdown
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https://issues.jboss.org/browse/TEIID-1990?page=com.atlassian.jira.plugin...
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Steven Hawkins commented on TEIID-1990:
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Yes, that is the likely issue. Teiid is adding a convert, but marking it as implicit so
it is not immediately visible (this is for the benefit of designer). Teiid 8.0 shows
implicit conversion more clearly and also provides a mechanism for translators to declare
support for only a subset of conversions. This implicit conversion then is preventing
pushdown.
It would be good to backport showing implicit conversion to 7.7.1 and to see why there
wasn't a more specific message in the debug log.
UNION pushdown
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Key: TEIID-1990
URL: https://issues.jboss.org/browse/TEIID-1990
Project: Teiid
Issue Type: Bug
Components: Query Engine
Affects Versions: 7.7
Reporter: Mark Addleman
Assignee: Steven Hawkins
Attachments: plan.txt, plan.txt
I have SQL of the form
SELECT a FROM (
SELECT a FROM ds.t1 UNION
SELECT a FROM ds.t2
) t
The execution factory extends JDBCExecutionFactory and supports everything except row
offset. It appears that the two unioned SELECTs are being executed as separate statements
rather than the entire unioned set being pushed down to the datasource.
Attached is plan
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