viirya commented on issue #244:
URL: https://github.com/apache/iceberg-rust/issues/244#issuecomment-2022062466

   > > I think this Implement sth like ArrowProjectionVisitor is for the 
following two items?
   > 
   > Yes, but with one extra requirement: reconstructing struct arrays. For 
example, when we select (`person.address.street`, `person.name`], we have 
projection mask `[1,2]`, and the returned schema is
   > 
   > ```
   > schema {
   >   struct person {
   >      struct address {
   >         string street
   >      }
   >      string name
   >   }
   > }
   > ```
   > 
   > But what we expect is
   > 
   > ```
   > schema {
   >    string person
   >    string name
   > }
   > ```
   
   Yea. I think the Parquet reader cannot return the flatten schema but the 
pruned struct `person`. Like in query engines such as Spark, we need an 
additional projection to project the pruned `person` to flatten two root 
columns `person` and `name`.
   
   


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