Struct PageTable

pub struct PageTable { /* private fields */ }

Page lookup table.

Implementations

impl PageTable

pub async fn load<'a>( reader: &dyn Reader, position: usize, min_field_id: i32, max_field_id: i32, num_batches: i32, ) -> Result<Self>

Load PageTable from disk.

Parameters:

• position: The start position in the file where the page table is stored.
• min_field_id: The smallest field_id that is present in the schema.
• max_field_id: The largest field_id that is present in the schema.
• num_batches: The number of batches in the file.

The page table is stored as an array. The on-disk size is determined based on the min_field_id, max_field_id, and num_batches parameters. If these are incorrect, the page table will not be read correctly.

The full sequence of field ids min_field_id..=max_field_id will be loaded. Non-existent pages will be represented as (0, 0) in the page table. Pages can be non-existent because they are not present in the file, or because they are struct fields which have no data pages.

pub async fn write( &self, writer: &mut dyn Writer, min_field_id: i32, ) -> Result<usize>

Write PageTable to disk.

min_field_id is the smallest field_id that is present in the schema. This might be a struct field, which has no data pages, but it still must be serialized to the page table per the format spec.

Any (field_id, batch_id) combinations that are not present in the page table will be written as (0, 0) to indicate an empty page. This includes any holes in the field ids as well as struct fields which have no data pages.

pub fn set(&mut self, field_id: i32, batch: i32, page_info: PageInfo)

Set page lookup info for a page identified by (column, batch) pair.

pub fn get(&self, field_id: i32, batch: i32) -> Option<&PageInfo>

Trait Implementations

impl Clone for PageTable

fn clone(&self) -> PageTable

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PageTable

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

Formats the value using the given formatter.

impl DeepSizeOf for PageTable

fn deep_size_of_children(&self, context: &mut Context) -> usize

Returns an estimation of the heap-managed storage of this object. This does not include the size of the object itself.

fn deep_size_of(&self) -> usize

Returns an estimation of a total size of memory owned by the object, including heap-managed storage.

impl Default for PageTable

fn default() -> PageTable

Returns the “default value” for a type.

impl PartialEq for PageTable

fn eq(&self, other: &PageTable) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for PageTable