thinkharderdev commented on code in PR #2526:
URL: https://github.com/apache/arrow-rs/pull/2526#discussion_r950334989
##########
parquet/src/arrow/async_reader.rs:
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@@ -139,6 +143,80 @@ pub trait AsyncFileReader: Send {
/// allowing fine-grained control over how metadata is sourced, in
particular allowing
/// for caching, pre-fetching, catalog metadata, etc...
fn get_metadata(&mut self) -> BoxFuture<'_, Result<Arc<ParquetMetaData>>>;
+
+ /// Provides asynchronous access to the the page index for each column
chunk in a
+ /// row group. Will panic if `row_group_idx` is greater than or equal to
`num_row_groups`
+ fn get_column_indexes(
+ &mut self,
+ metadata: Arc<ParquetMetaData>,
+ row_group_idx: usize,
+ ) -> BoxFuture<'_, Result<Vec<Index>>> {
+ async move {
+ let chunks = metadata.row_group(row_group_idx).columns();
+
+ let (offset, lengths) =
index_reader::get_index_offset_and_lengths(chunks)?;
+ let length = lengths.iter().sum::<usize>();
+
+ if length == 0 {
+ return Ok(vec![Index::NONE; chunks.len()]);
+ }
+
+ //read all need data into buffer
+ let data = self
+ .get_bytes(offset as usize..offset as usize + length)
Review Comment:
Yeah, that makes sense.
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