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https://issues.apache.org/jira/browse/ASTERIXDB-3479?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ian Maxon updated ASTERIXDB-3479:
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Labels: triaged (was: )
> Enumeration and reordering of UNNEST operator
> ---------------------------------------------
>
> Key: ASTERIXDB-3479
> URL: https://issues.apache.org/jira/browse/ASTERIXDB-3479
> Project: Apache AsterixDB
> Issue Type: Improvement
> Components: COMP - Compiler
> Reporter: Vijay Sarathy
> Priority: Major
> Labels: triaged
>
> In CH2 q3,
> {code:java}
> SELECT o.o_id, o.o_w_id, o.o_d_id, SUM(ol.ol_amount) AS revenue, o.o_entry_d
> FROM customer c, neworder no, orders o, o.o_orderline ol
> WHERE c.c_state LIKE 'A%'
> AND c.c_id = o.o_c_id
> AND c.c_w_id = o.o_w_id
> AND c.c_d_id = o.o_d_id
> AND no.no_w_id = o.o_w_id
> AND no.no_d_id = o.o_d_id
> AND no.no_o_id = o.o_id
> AND o.o_entry_d < '2017-03-15 00:00:00.000000'
> GROUP BY o.o_id, o.o_w_id, o.o_d_id, o.o_entry_d
> ORDER BY revenue DESC, o.o_entry_d;
> {code}
> the filter on orders is not very selective and returns ~50% of the rows, but
> the filter on customer is much more selective, and the C-O join is therefore
> much smaller (about 6% of the size of O). Since there are no references to
> the unnested part of O (except in the select clause), the unnest on O can be
> moved up after the C-O join or even after the final join. This will improve
> performance quite a bit. CBO needs to treat UNNEST like a "local join" and be
> able to enumerate and reorder it like regular join operators.
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