Struct MiniBlockLayout

pub struct MiniBlockLayout {
    pub rep_compression: Option<ArrayEncoding>,
    pub def_compression: Option<ArrayEncoding>,
    pub value_compression: Option<ArrayEncoding>,
    pub dictionary: Option<ArrayEncoding>,
    pub layers: Vec<i32>,
    pub repetition_index_depth: u32,
    pub num_items: u64,
}

/ A layout used for pages where the data is small / / In this case we can fit many values into a single disk sector and transposing buffers is / expensive. As a result, we do not transpose the buffers but compress the data into small / chunks (called mini blocks) which are roughly the size of a disk sector.

Fields

rep_compression: Option<ArrayEncoding>

Description of the compression of repetition levels (e.g. how many bits per rep)

def_compression: Option<ArrayEncoding>

Description of the compression of definition levels (e.g. how many bits per def)

value_compression: Option<ArrayEncoding>

Description of the compression of values

dictionary: Option<ArrayEncoding>

Dictionary data

layers: Vec<i32>

The meaning of each repdef layer, used to interpret repdef buffers correctly

repetition_index_depth: u32

The depth of the repetition index.

If there is repetition then the depth must be at least 1. If there are many layers of repetition then deeper repetition indices will support deeper nested random access. For example, given 5 layers of repetition then the repetition index depth must be at least 3 to support access like rows[50][17][3].

We require repetition_index_depth + 1 u64 values per mini-block to store the repetition index if the repetition_index_depth is greater than 0. The +1 is because we need to store the number of “leftover items” at the end of the chunk. Otherwise, we wouldn’t have any way to know if the final item in a chunk is valid or not.

num_items: u64

The page already records how many rows are in the page. For mini-block we also need to know how many “items” are in the page. A row and an item are the same thing unless the page has lists.

Implementations

impl MiniBlockLayout

pub fn layers( &self, ) -> FilterMap<Cloned<Iter<'_, i32>>, fn(_: i32) -> Option<RepDefLayer>>

Returns an iterator which yields the valid enum values contained in layers.

pub fn push_layers(&mut self, value: RepDefLayer)

Appends the provided enum value to layers.

Trait Implementations

impl Clone for MiniBlockLayout

fn clone(&self) -> MiniBlockLayout

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for MiniBlockLayout

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

Formats the value using the given formatter.

impl Default for MiniBlockLayout

fn default() -> Self

Returns the “default value” for a type.

impl Message for MiniBlockLayout

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 Name for MiniBlockLayout

const NAME: &'static str = "MiniBlockLayout"

Simple name for this Message. This name is the same as it appears in the source .proto file, e.g. FooBar.

const PACKAGE: &'static str = "lance.encodings"

Package name this message type is contained in. They are domain-like and delimited by ., e.g. google.protobuf.

fn full_name() -> String

Fully-qualified unique name for this Message. It’s prefixed with the package name and names of any parent messages, e.g. google.rpc.BadRequest.FieldViolation. By default, this is the package name followed by the message name. Fully-qualified names must be unique within a domain of Type URLs.

fn type_url() -> String

Type URL for this Message, which by default is the full name with a leading slash, but may also include a leading domain name, e.g. type.googleapis.com/google.profile.Person. This can be used when serializing into the google.protobuf.Any type.

impl PartialEq for MiniBlockLayout

fn eq(&self, other: &MiniBlockLayout) -> 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 MiniBlockLayout