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https://issues.apache.org/jira/browse/DRILL-7278?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16854846#comment-16854846
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ASF GitHub Bot commented on DRILL-7278:
---------------------------------------
arina-ielchiieva commented on pull request #1797: DRILL-7278: Refactor result
set loader projection mechanism
URL: https://github.com/apache/drill/pull/1797#discussion_r289936396
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/physical/impl/scan/project/package-info.java
##########
@@ -71,9 +141,72 @@
* distinct class. Classes combine via composition to create a "framework"
* suitable for each kind of reader: whether it be early or late schema,
* file-based or something else, etc.
+ *
+ * <h4>Nuances of Reader-Level Projection</h4>
+ *
+ * We've said that the scan-level projection identifies what the query
+ * <i>wants</i>. We've said that the reader identifies what the external
+ * data actually <i>is</i>. We've mentioned how we bridge between the
+ * two. Here we explore this in more detail.
+ * <p>
+ * Run-time schema resolution occurs at various stages:
* <p>
+ * <ul>
+ * <li>The per-column resolution identified earlier: matching types,
+ * type conversion, and so on.</li>
+ * <li>The reader will provides some set of columns. We don't know which
Review comment:
```suggestion
* <li>The reader will provide some set of columns. We don't know which
```
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> Refactor result set loader projection mechanism
> -----------------------------------------------
>
> Key: DRILL-7278
> URL: https://issues.apache.org/jira/browse/DRILL-7278
> Project: Apache Drill
> Issue Type: Improvement
> Affects Versions: 1.16.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Priority: Major
> Fix For: 1.17.0
>
>
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