opensourcegeek commented on issue #4328:
URL: https://github.com/apache/arrow-rs/issues/4328#issuecomment-2102395866
I think I get the context now, after going through the
`RowGroupPruningStatistics` code in datafusion (relevant code below for future
reference) - thanks for that pointer @alamb.
```rust
fn column(&self, name: &str) -> Option<(&ColumnChunkMetaData,
&FieldRef)> {
let (idx, field) = parquet_column(self.parquet_schema,
self.arrow_schema, name)?;
Some((self.row_group_metadata.column(idx), field))
}
fn min_values(&self, column: &Column) -> Option<ArrayRef> {
let (column, field) = self.column(&column.name)?;
// here we already have mapped the statistics relevant just for the
column
min_statistics(field.data_type(),
std::iter::once(column.statistics())).ok()
}
```
I was thinking that ParquetStatistics iterator that is getting passed into
the function, was for _all_ columns in a row group. That's where I got a bit
confused. I'll continue with it, documenting this as it was a light bulb moment
for me and may help someone looking into this in the future.
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