Struct ModuloShardChooser 

pub struct ModuloShardChooser { /* private fields */ }

A simple modulo-based shard chooser for numeric shard keys.

Routes based on shard_key % shard_count, producing shard names like shard_0, shard_1, etc.

This is suitable for evenly distributed numeric keys (e.g., auto-increment IDs). Not suitable for sequential inserts (hotspotting on latest shard) or non-numeric keys.

Implementations

impl ModuloShardChooser

pub fn new(shard_count: usize) -> Self

Create a new modulo shard chooser with the given number of shards.

Shards are named shard_0, shard_1, …, shard_{n-1}.

Panics

Panics if shard_count is 0, as this would cause division by zero when routing to shards.

pub fn with_prefix(self, prefix: impl Into<String>) -> Self

Set a custom prefix for shard names (default: “shard_”).

pub fn shard_count(&self) -> usize

Get the shard count.

Trait Implementations

impl Clone for ModuloShardChooser

fn clone(&self) -> ModuloShardChooser

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ModuloShardChooser

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

Formats the value using the given formatter.

impl ShardChooser for ModuloShardChooser

fn choose_for_model(&self, shard_key: &Value) -> String

Choose the shard for a model based on its shard key value.

fn choose_for_query(&self, hints: &QueryHints) -> Vec<String>

Choose which shards to query based on query hints.

fn all_shards(&self) -> Vec<String>

Get all registered shard names.