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https://issues.apache.org/jira/browse/SPARK-12449?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15151880#comment-15151880
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Max Seiden commented on SPARK-12449:
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Yea, that seems to be the case. There's code in the DataSourceStrategy that
specifically resolves aliases, but the filtered scan case is pretty narrow
relative to an expression tree.
+1 for a generic way to avoid double execution of operations. On the flip, a
boolean check would drop a neat property of "unhandledFilters" which is that it
can accept a subset of what the planner tries to push down.
> Pushing down arbitrary logical plans to data sources
> ----------------------------------------------------
>
> Key: SPARK-12449
> URL: https://issues.apache.org/jira/browse/SPARK-12449
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Reporter: Stephan Kessler
> Attachments: pushingDownLogicalPlans.pdf
>
>
> With the help of the DataSource API we can pull data from external sources
> for processing. Implementing interfaces such as {{PrunedFilteredScan}} allows
> to push down filters and projects pruning unnecessary fields and rows
> directly in the data source.
> However, data sources such as SQL Engines are capable of doing even more
> preprocessing, e.g., evaluating aggregates. This is beneficial because it
> would reduce the amount of data transferred from the source to Spark. The
> existing interfaces do not allow such kind of processing in the source.
> We would propose to add a new interface {{CatalystSource}} that allows to
> defer the processing of arbitrary logical plans to the data source. We have
> already shown the details at the Spark Summit 2015 Europe
> [https://spark-summit.org/eu-2015/events/the-pushdown-of-everything/]
> I will add a design document explaining details.
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