]
Steven Hawkins commented on TEIID-2902:
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Not making much head way here as all of the sorting logic / join logic is fairly entangled
and generally expects to read all values as part of the sorting operation (for example if
any prefetch is performed, we'll read everything even before performing a single pass
sort).
It looks like it would be easier to start over somewhat to avoid attempting to retro-fit
too much.
More incremental join when a limit is present
---------------------------------------------
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
Fix For: 8.8
For SQL like:
SELECT
t1.column1,
t2.column1
FROM
schema1.table1 t1,
schema2.table1 t2
WHERE
t1.column2=t2.column2
LIMIT 100
Teiid may get 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.