Struct RowGroupPageIndex 

pub struct RowGroupPageIndex {
    row_group_idx: usize,
    page_index: Option<Arc<dyn PageIndexProvider>>,
}

Provides convenient access to page index data for a specific row group

This struct wraps a PageIndexProvider and automatically applies the row group index, simplifying access to column and offset indexes for a single row group. It is primarily used by readers to avoid repeatedly passing the row group index when accessing page-level metadata.

Example

use parquet::file::metadata::ParquetMetaData;

fn process_row_group_pages(metadata: &ParquetMetaData, row_group_idx: usize) -> Result<()> {
    // Create a row-group-specific view of the page index
    let rg_page_index = metadata.page_index_for_row_group(row_group_idx);

    // Now access column indexes without specifying row_group_idx each time
    for col_idx in 0..metadata.file_metadata().schema_descr().num_columns() {
        if let Some(col_idx_data) = rg_page_index.column_index(col_idx) {
            println!("Column {} has {} pages", col_idx, col_idx_data.num_pages());
        }
    }
    Ok(())
}

Fields

row_group_idx: usize

page_index: Option<Arc<dyn PageIndexProvider>>

Implementations

impl RowGroupPageIndex

pub fn new( row_group_idx: usize, page_index: Option<Arc<dyn PageIndexProvider>>, ) -> Self

Creates a new RowGroupPageIndex for the specified row group

Arguments

• row_group_idx - The index of the row group within the file
• page_index - Optional page index provider containing the index data

pub fn column_index(&self, column_idx: usize) -> Option<&ColumnIndexMetaData>

Returns the column index for a specific column in this row group

This is a convenience method that wraps PageIndexProvider::column_index, automatically applying the row group index stored in this struct.

Returns

• Some(&ColumnIndexMetaData) - Column index is available with page-level statistics
• None - Index unavailable (no page index, column out of bounds, or no statistics)

See Also

• PageIndexProvider::column_index for more details on column indexes

pub fn offset_index(&self, column_idx: usize) -> Option<&OffsetIndexMetaData>

Returns the offset index for a specific column in this row group

This is a convenience method that wraps PageIndexProvider::offset_index, automatically applying the row group index stored in this struct.

Returns

• Some(&OffsetIndexMetaData) - Offset index is available with page locations
• None - Index unavailable (no page index, column out of bounds)

See Also

• PageIndexProvider::offset_index for more details on offset indexes

pub fn page_locations(&self, column_idx: usize) -> Option<&Vec<PageLocation>>

Returns the physical locations of all data pages for a specific column in this row group

This is a convenience method that wraps PageIndexProvider::page_locations, automatically applying the row group index stored in this struct.

This enables direct I/O to specific pages without reading the entire column chunk.

Returns

• Some(&Vec<PageLocation>) - Vector of page locations if offset index exists
• None - Offset index not available for this column

See Also

• PageIndexProvider::page_locations for more details on page locations

pub fn num_data_pages(&self, column_idx: usize) -> Option<usize>

Returns the expected number of data pages for a specific column in this row group

This count includes only data pages, not dictionary pages or other metadata pages.

This is a convenience method that wraps PageIndexProvider::num_data_pages, automatically applying the row group index stored in this struct.

Returns

• Some(usize) - Number of data pages if any index is available
• None - No index information available for this column

See Also

• PageIndexProvider::num_data_pages for more details

Trait Implementations

impl Debug for RowGroupPageIndex

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.