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ShardCodec

Struct ShardCodec 

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pub struct ShardCodec { /* private fields */ }
Expand description

Packs a physical shard number into the high bits of a u64 id, so any id (primary key or a shard-encoded foreign key) self-describes its shard.

With shard_bits = 12, ids carry a 12-bit shard (up to 4096 shards) and a 52-bit per-shard sequence — ample for app-generated ids. Auto-increment is not used for sharded entities (it can’t carry the shard); the app composes the id with compose.

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impl ShardCodec

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pub const DEFAULT: ShardCodec

A sensible default: 12 shard bits (up to 4096 shards) + 52 sequence bits. Surfaces that don’t need a custom layout can share this so their id schemes agree (and stay portable between a single-DB and a fleet).

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pub const fn new(shard_bits: u32) -> Self

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pub const fn seq_bits(&self) -> u32

Bits available for the per-shard sequence.

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pub const fn shard_of(&self, id: u64) -> u32

The shard number encoded in id.

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pub const fn local_of(&self, id: u64) -> u64

The per-shard local part of id.

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pub const fn compose(&self, shard: u32, local: u64) -> u64

Compose a full id from a shard number and a per-shard local sequence.

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impl Clone for ShardCodec

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fn clone(&self) -> Self

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from source. Read more
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impl Copy for ShardCodec

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impl Debug for ShardCodec

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

Formats the value using the given formatter. Read more
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impl Eq for ShardCodec

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impl PartialEq for ShardCodec

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

Equality operator ==. Read more
1.0.0 (const: unstable) · Source§

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

Inequality operator !=. Read more
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impl ShardLocator for ShardCodec

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fn locate(&self, key: u64) -> ShardId

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impl StructuralPartialEq for ShardCodec

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = !

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, !>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.