Struct Metadata

pub struct Metadata {
    pub manifest_position: u64,
    pub batch_offsets: Vec<i32>,
    pub page_table_position: u64,
    pub statistics: Option<StatisticsMetadata>,
}

Metadata of one Lance file.

Fields

manifest_position: u64

Position of the manifest in the file. If it is zero, the manifest is stored externally.

batch_offsets: Vec<i32>

Logical offsets of each chunk group, i.e., number of the rows in each chunk.

page_table_position: u64

The file position that page table is stored.

A page table is a matrix of N x M x 2, where N = num_fields, and M = num_batches. Each cell in the table is a pair of <position:int64, length:int64> of the page. Both position and length are int64 values. The <position, length> of all the pages in the same column are then contiguously stored.

Every field that is a part of the file will have a run in the page table. This includes struct columns, which will have a run of length 0 since they don’t store any actual data.

For example, for the column 5 and batch 4, we have:

   position = page_table[5][4][0];
   length = page_table[5][4][1];

statistics: Option<StatisticsMetadata>

Trait Implementations

impl Clone for Metadata

fn clone(&self) -> Metadata

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Metadata

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

Formats the value using the given formatter.

impl Default for Metadata

fn default() -> Self

Returns the “default value” for a type.

impl From<&Metadata> for Metadata

fn from(m: &Metadata) -> Self

Converts to this type from the input type.

impl Message for Metadata

fn encoded_len(&self) -> usize

Returns the encoded length of the message without a length delimiter.

fn clear(&mut self)

Clears the message, resetting all fields to their default.

fn encode(&self, buf: &mut impl BufMut) -> Result<(), EncodeError>

where Self: Sized,

Encodes the message to a buffer.

fn encode_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message to a newly allocated buffer.

fn encode_length_delimited( &self, buf: &mut impl BufMut, ) -> Result<(), EncodeError>

where Self: Sized,

Encodes the message with a length-delimiter to a buffer.

fn encode_length_delimited_to_vec(&self) -> Vec<u8>

where Self: Sized,

Encodes the message with a length-delimiter to a newly allocated buffer.

fn decode(buf: impl Buf) -> Result<Self, DecodeError>

where Self: Default,

Decodes an instance of the message from a buffer.

fn decode_length_delimited(buf: impl Buf) -> Result<Self, DecodeError>

where Self: Default,

Decodes a length-delimited instance of the message from the buffer.

fn merge(&mut self, buf: impl Buf) -> Result<(), DecodeError>

where Self: Sized,

Decodes an instance of the message from a buffer, and merges it into self.

fn merge_length_delimited(&mut self, buf: impl Buf) -> Result<(), DecodeError>

where Self: Sized,

Decodes a length-delimited instance of the message from buffer, and merges it into self.

impl PartialEq for Metadata

fn eq(&self, other: &Metadata) -> 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 TryFrom<Metadata> for Metadata

type Error = Error

The type returned in the event of a conversion error.

fn try_from(m: Metadata) -> Result<Self>

Performs the conversion.

impl StructuralPartialEq for Metadata