ASF GitHub Bot commented on DRILL-7509:

KazydubB commented on pull request #1954: DRILL-7509: Incorrect TupleSchema is 
created for DICT column when querying Parquet files
URL: https://github.com/apache/drill/pull/1954#discussion_r366851158

 File path: 
 @@ -50,7 +51,7 @@ public static ColumnMetadata getColumnMetadata(SchemaPath 
schemaPath, TupleMetad
     while (!colPath.isLastPath() && colMetadata != null) {
       if (colMetadata.isDict()) {
         // get dict's value field metadata
-        colMetadata = 
+        colMetadata = colMetadata.tupleSchema().metadata(1);
 Review comment:
   That's a good point, a `keyMetadata()` and `valueMetadata()` can be defined 
in `DictColumnMetadata` (as an another to what you've suggested; but that'd 
require casting).
   I don't see a strong need to have a static mapping of `key` and `value` for 
`DICT`, as the existing mechanism does the work and suits well for the case (at 
least, to my understanding). But I do agree that hiding this implementation 
details is better practice. Will introduce a new method.
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> Incorrect TupleSchema is created for DICT column when querying Parquet files
> ----------------------------------------------------------------------------
>                 Key: DRILL-7509
>                 URL: https://issues.apache.org/jira/browse/DRILL-7509
>             Project: Apache Drill
>          Issue Type: Bug
>    Affects Versions: 1.16.0
>            Reporter: Bohdan Kazydub
>            Assignee: Bohdan Kazydub
>            Priority: Major
>             Fix For: 1.18.0
> When {{DICT}} column is queried from Parquet file, its {{TupleSchema}} 
> contains nested element, e.g. `map`, itself contains `key` and `value` 
> fields, rather than containing the `key` and `value` fields in the {{DICT}}'s 
> {{TupleSchema}} itself. The nested element, `map`, comes from the inner 
> structure of Parquet's {{MAP}} (which corresponds to Drill's {{DICT}}) 
> representation.

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