[teiid-issues] [JBoss JIRA] (TEIID-2902) LIMIT is not passing to subqueries

[Ivan Chan (JIRA)]

Ivan Chan created TEIID-2902:
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             Summary: LIMIT is not passing to subqueries
                 Key: TEIID-2902
                 URL: https://issues.jboss.org/browse/TEIID-2902
             Project: Teiid
          Issue Type: Enhancement
          Components: Query Engine
    Affects Versions: 8.7
            Reporter: Ivan Chan
            Assignee: Steven Hawkins


it does not push down the limit to the underlying datasources. What I means is that if SQL looks:

SELECT 
     t1.column1, 
     t2.column1
FROM 
     schema1.table1 t1, 
     schema2.table1 t2
WHERE 
     t1.column2=t2.column2
LIMIT 100

But Teiid will ask for the whole schema1.table1 content and the whole schema2.table1 content, do the join in memory and then, limit the resultset to 100 records.

However, I think teiid can fetch smaller set of data then do a join.  If the join result set is less than number of rows asking,  keep fetching next set of data and do a join until hits the limit number.

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