Struct PageIndexBuilder 

pub struct PageIndexBuilder {
    column_indexes: Option<Vec<Vec<Option<ColumnIndexMetaData>>>>,
    offset_indexes: Option<Vec<Vec<Option<OffsetIndexMetaData>>>>,
}

Builder for constructing PageIndex structures

It supports:

• Populating column indexes for predicate columns (for page filtering)
• Populating offset indexes for projected columns (for direct I/O)
• Automatic conversion of empty structures to None to save memory

Fields

column_indexes: Option<Vec<Vec<Option<ColumnIndexMetaData>>>>

offset_indexes: Option<Vec<Vec<Option<OffsetIndexMetaData>>>>

Implementations

impl PageIndexBuilder

fn empty_index<T>( num_row_groups: usize, num_columns: usize, ) -> Option<Vec<Vec<Option<T>>>>

Creates an empty index structure with space for the specified number of row groups and columns

Returns Some containing a nested vector structure where all entries are initialized to None. The outer vector has one entry per row group, and each inner vector has one entry per column.

Type Parameters

• T - The type of index this is to be, either ColumnIndexMetaData or OffsetIndexMetaData

pub fn new(num_row_groups: usize, num_columns: usize) -> Self

Creates a new PageIndexBuilder with space allocated for both column and offset indexes

This allocates empty index structures for the specified number of row groups and columns. All index entries are initialized to None and can be populated using put_column_index and put_offset_index.

pub(crate) fn new_from(page_index: PageIndex) -> Self

Creates a new PageIndexBuilder from an existing PageIndex

This takes ownership of the index structures from the provided PageIndex, allowing them to be modified and rebuilt. Useful for updating existing page indexes.

pub fn allocate_column_indexes( &mut self, num_row_groups: usize, num_columns: usize, )

Allocates space for column indexes

This allocates an empty index structure for the specified number of row groups and columns. All index entries are initialized to None and can be populated using put_column_index.

This can be used to add column index storage to a builder that lacks one (either a Default builder, or one created from a PageIndex without column indexes).

pub fn allocate_offset_indexes( &mut self, num_row_groups: usize, num_columns: usize, )

Allocates space for offset indexes

This allocates an empty index structure for the specified number of row groups and columns. All index entries are initialized to None and can be populated using put_offset_index.

This can be used to add offset index storage to a builder that lacks one (either a Default builder, or one created from a PageIndex without offset indexes).

pub fn put_column_index( &mut self, column_index: ColumnIndexMetaData, row_group_idx: usize, column_idx: usize, )

Sets the column index for a specific row group and column

If column indexes were not allocated (see Self::allocate_column_indexes), or the row group or column index is out of bounds, this method does nothing.

pub fn put_offset_index( &mut self, offset_index: OffsetIndexMetaData, row_group_idx: usize, column_idx: usize, )

Sets the offset index for a specific row group and column

If offset indexes were not allocated (see Self::allocate_offset_indexes), or the row group or column index is out of bounds, this method does nothing.

fn is_empty_index<T>(index: Option<&Vec<Vec<Option<T>>>>) -> bool

Checks if an index structure is entirely empty (all entries are None)

pub fn build(self) -> PageIndex

Consumes the builder and returns a PageIndex

If an index structure was allocated but remains entirely empty (all entries are None), it will be converted to None in the final PageIndex. This ensures that:

• Empty structures don’t consume memory unnecessarily
• PageIndex::has_column_indexes() and PageIndex::has_offset_indexes() correctly return false for unpopulated indexes

Trait Implementations

impl Default for PageIndexBuilder

fn default() -> PageIndexBuilder

Returns the “default value” for a type.

impl From<PageIndex> for PageIndexBuilder

fn from(page_index: PageIndex) -> Self

Converts to this type from the input type.