Struct Chunk 

pub struct Chunk { /* private fields */ }

A batch of columns of equal length.

Implementations

impl Chunk

pub fn new(columns: Vec<Vector>) -> Result<Self>

A chunk of columns, taking the row count from the first of them.

Errors

If the columns are not all the same length, or if there are more rows than VECTOR_SIZE.

pub fn with_rows(columns: Vec<Vector>, rows: usize) -> Result<Self>

A chunk of columns that is rows long, for the case where there are no columns to take the count from.

Errors

If any column is not rows long, or if rows is more than VECTOR_SIZE.

pub fn empty(types: &[LogicalType]) -> Self

A chunk of the given types with no rows in it.

What a scan of an empty table returns and what an operator returns when it is done. The types are kept, because a consumer asks a chunk what its columns are before it asks whether there are any.

pub fn columns(&self) -> &[Vector]

The columns.

pub fn column(&self, index: usize) -> Result<&Vector>

One column.

Errors

If there is no column at index.

pub fn into_columns(self) -> Vec<Vector>

The columns, given up.

pub fn width(&self) -> usize

How many columns.

pub fn len(&self) -> usize

How many rows.

pub fn is_empty(&self) -> bool

Whether there are no rows.

pub fn types(&self) -> Vec<LogicalType>

The type of each column.

pub fn value_at(&self, row: usize, column: usize) -> Value

The value at a row and a column, or null if either is past the end.

The slow path, same as Vector::value_at. It is what a result set is read out with and what a test asserts on.

pub fn row(&self, row: usize) -> impl Iterator<Item = Value> + '_

One row, left to right.

pub fn select(self, selection: &Selection) -> Result<Self>

The rows a selection kept, without moving any of the values.

Every column becomes a dictionary vector whose codes are the selection, which is the form spec/07-execution.md section 7.1 asks a filter to produce rather than compacting. It takes the chunk by value because that is what makes it free: the payload is moved into the new vector rather than copied, so a filter that keeps one row in a thousand still costs the selection and nothing else.

Errors

If the selection points past the end of the chunk.

pub fn project(self, positions: &[usize]) -> Result<Self>

The columns at the given positions, in that order.

A position may appear twice, which is what SELECT x, x FROM t is, and the second one costs a copy. Every other position is moved.

Errors

If a position is past the end of the chunk.

pub fn flatten(&self) -> Result<Self>

The same rows with every column in flat form.

Costs a copy per column that was not already flat. It is here for the result set at the top of a query, where the dictionary vectors a filter left behind would otherwise be handed to a caller who has to understand them.

Errors

If a column has a type that cannot be stored flat yet, which today means the nested types.

Trait Implementations

impl Clone for Chunk

fn clone(&self) -> Chunk

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Chunk

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

Formats the value using the given formatter.

impl PartialEq for Chunk

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Chunk