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https://issues.apache.org/jira/browse/DRILL-6312?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Pritesh Maker updated DRILL-6312:
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Issue Type: New Feature (was: Bug)
> Enable pushing of cast expressions to the scanner for better schema discovery.
> ------------------------------------------------------------------------------
>
> Key: DRILL-6312
> URL: https://issues.apache.org/jira/browse/DRILL-6312
> Project: Apache Drill
> Issue Type: New Feature
> Components: Execution - Relational Operators, Query Planning &
> Optimization
> Affects Versions: 1.13.0
> Reporter: Hanumath Rao Maduri
> Priority: Major
>
> Drill is a schema less engine which tries to infer the schema from disparate
> sources at the read time. Currently the scanners infer the schema for each
> batch depending upon the data for that column in the corresponding batch.
> This solves many uses cases but can error out when the data is too different
> between batches like int and array[int] etc... (There are other cases as well
> but just to give one example).
> There is also a mechanism to create a view by type casting the columns to
> appropriate type. This solves issues in some cases but fails in many other
> cases. This is due to the fact that cast expression is not being pushed down
> to the scanner but staying at the project or filter etc operators up the
> query plan.
> This JIRA is to fix this by propagating the type information embedded in the
> cast function to the scanners so that scanners can cast the incoming data
> appropriately.
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