Struct Batch 

pub struct Batch {
    starting_seq_number: Option<u64>,
    operations: Vec<BatchElement>,
}

A set of operations to perform atomically.

The updates are applied in the order in which they are added to the batch.

Examples

use raindb::Batch;

let mut batch = Batch::new();
batch
    .add_put("key".into(), "v1".into())
    .add_delete("key".into())
    .add_put("key".into(), "v2".into())
    .add_put("key".into(), "v3".into());

// The value of "key" will be "v3" when the batch is applied to the database.

Serialization

A batch has the following layout when serialized:

1. The starting sequence number as a 64-bit fixed-length integer
2. The number operations in the batch as a 32-bit fixed-length integer
3. Serialized BatchElement’s. See the BatchElement docs their serialization format.

Fields

starting_seq_number: Option<u64>

The starting sequence number for this batch of operations.

This is set internally when a write is actually executed.

operations: Vec<BatchElement>

A list of operations to perform in a batch.

Implementations

impl Batch

Public methods

pub fn new() -> Self

Create an empty Batch.

pub fn add_put(&mut self, key: Vec<u8>, value: Vec<u8>) -> &mut Self

Add a Put operation to the batch.

key - the user provided key to associate with the value to be stored value - the value to be stored in the database

pub fn add_delete(&mut self, key: Vec<u8>) -> &mut Self

Add a Delete operation to the batch.

key - the user provided key to associate with the value to be stored

pub fn clear(&mut self) -> &mut Self

Clear the operations added to the batch.

pub fn iter(&self) -> Iter<'_, BatchElement>

Get an iterator over references to operations added to the batch.

pub fn len(&self) -> usize

Get the number of entries within the batch.

pub fn is_empty(&self) -> bool

Returns true if the batch does not have any operations. Otherwise, returns false.

impl Batch

Crate-only methods

pub(crate) fn get_approximate_size(&self) -> usize

Get the approximate size of the database changes that would be caused by this batch.

pub(crate) fn set_starting_seq_number(&mut self, seq_number: u64)

The the starting sequence number of the batch.

pub(crate) fn get_starting_seq_number(&self) -> Option<u64>

Get the starting sequence number of the batch.

pub(crate) fn append_batch(&mut self, batch_to_append: &Batch)

Append the operations from another batch to the operations of the current batch.

This is usually done to create a group commit and reduce write latency.

pub(crate) fn add_operation(&mut self, batch_element: BatchElement)

Append an operation.

Trait Implementations

impl Default for Batch

fn default() -> Self

Returns the “default value” for a type.

impl From<&Batch> for Vec<u8>

fn from(batch: &Batch) -> Vec<u8>

Serialize a Batch to bytes.

impl PartialEq for Batch

fn eq(&self, other: &Batch) -> 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<&[u8]> for Batch

type Error = RainDBError

The type returned in the event of a conversion error.

fn try_from(buf: &[u8]) -> Result<Self, Self::Error>

Performs the conversion.

impl Eq for Batch

impl StructuralPartialEq for Batch