Enum LockKey

pub enum LockKey {
    Filesystem,
    Flush {
        object_id: u64,
    },
    ObjectAttribute {
        store_object_id: u64,
        object_id: u64,
        attribute_id: u64,
    },
    Object {
        store_object_id: u64,
        object_id: u64,
    },
    ProjectId {
        store_object_id: u64,
        project_id: u64,
    },
    Truncate {
        store_object_id: u64,
        object_id: u64,
    },
}

When creating a transaction, locks typically need to be held to prevent two or more writers trying to make conflicting mutations at the same time. LockKeys are used for this. NOTE: Ordering is important here! The lock manager sorts the list of locks in a transaction to acquire them in a consistent order, but there are special cases for the Filesystem lock and the Flush lock. The Filesystem lock is taken by every transaction and is done so first, as part of the TxnGuard. The Flush lock is taken when we flush an LSM tree (e.g. an object store), and is held for several transactions. As such, it must come first in the lock acquisition ordering, so that other transactions using the Flush lock have the same ordering as in flushing.

Variants

Filesystem

Locks the entire filesystem.

Flush

Used to lock flushing an object.

Fields

object_id: u64

ObjectAttribute

Used to lock changes to a particular object attribute (e.g. writes).

Fields

store_object_id: u64

object_id: u64

attribute_id: u64

Object

Used to lock changes to a particular object (e.g. adding a child to a directory).

Fields

store_object_id: u64

object_id: u64

ProjectId

Fields

store_object_id: u64

project_id: u64

Truncate

Used to lock any truncate operations for a file.

Fields

store_object_id: u64

object_id: u64

Implementations

impl LockKey

pub const fn object_attribute( store_object_id: u64, object_id: u64, attribute_id: u64, ) -> Self

pub const fn object(store_object_id: u64, object_id: u64) -> Self

pub const fn flush(object_id: u64) -> Self

pub const fn truncate(store_object_id: u64, object_id: u64) -> Self

Trait Implementations

impl Clone for LockKey

fn clone(&self) -> LockKey

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for LockKey

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

Formats the value using the given formatter.

impl Hash for LockKey

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for LockKey

fn cmp(&self, other: &LockKey) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for LockKey

fn eq(&self, other: &LockKey) -> 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 PartialOrd for LockKey

fn partial_cmp(&self, other: &LockKey) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for LockKey

impl Eq for LockKey

impl StructuralPartialEq for LockKey