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https://issues.apache.org/jira/browse/ASTERIXDB-2913?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Michael J. Carey reassigned ASTERIXDB-2913:
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Assignee: Dmitry Lychagin
> Need "break up to make up" rewrite rule for unnested data
> ---------------------------------------------------------
>
> Key: ASTERIXDB-2913
> URL: https://issues.apache.org/jira/browse/ASTERIXDB-2913
> Project: Apache AsterixDB
> Issue Type: Bug
> Reporter: Michael J. Carey
> Assignee: Dmitry Lychagin
> Priority: Major
>
> Consider the following query using the Don Chamberlin book data:
>
> _USE DonCData;_
> _WITH flat_orders AS (SELECT orderno, custid, order_date, ship_date FROM
> orders),_
> _flat_items AS (SELECT o.orderno, i.* FROM orders o, o.items i)_
> _SELECT fo.*, fi.* FROM flat_orders fo, flat_items fi_
> _WHERE fo.orderno = fi.orderno;_
> Right now this query leads to two scans of orders - one for flat_orders and
> one for flat_items - followed by a join of the two.
> It seems like it should be possible to rewrite (under the hood) this query as
> simply:
> _USE DonCData;_
> _SELECT o.orderno, o.custid, o.order_date, o.ship_date, i.*_
> _FROM orders o, o.items i;_
> This capability could prove super-helpful in our future BI story. (Picture
> two flat views being exported for JDBC - it would be nice to be able to piece
> them back together for efficient querying under the hood.)
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