Enum ReadPreference

#[non_exhaustive]
pub enum ReadPreference {
    Primary,
    Secondary {
        options: Option<ReadPreferenceOptions>,
    },
    PrimaryPreferred {
        options: Option<ReadPreferenceOptions>,
    },
    SecondaryPreferred {
        options: Option<ReadPreferenceOptions>,
    },
    Nearest {
        options: Option<ReadPreferenceOptions>,
    },
}

Specifies how the driver should route a read operation to members of a replica set.

If applicable, tag_sets can be used to target specific nodes in a replica set, and max_staleness specifies the maximum lag behind the primary that a secondary can be to remain eligible for the operation. The max staleness value maps to the maxStalenessSeconds MongoDB option and will be sent to the server as an integer number of seconds.

See the MongoDB docs for more details.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Primary

Only route this operation to the primary.

Secondary

Only route this operation to a secondary.

Fields

options: Option<ReadPreferenceOptions>

PrimaryPreferred

Route this operation to the primary if it’s available, but fall back to the secondaries if not.

Fields

options: Option<ReadPreferenceOptions>

SecondaryPreferred

Route this operation to a secondary if one is available, but fall back to the primary if not.

Fields

options: Option<ReadPreferenceOptions>

Nearest

Route this operation to the node with the least network latency regardless of whether it’s the primary or a secondary.

Fields

options: Option<ReadPreferenceOptions>

Trait Implementations

impl Clone for ReadPreference

fn clone(&self) -> ReadPreference

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ReadPreference

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ReadPreference

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for ReadPreference

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

Formats the value using the given formatter.

impl From<ReadPreference> for SelectionCriteria

fn from(read_pref: ReadPreference) -> Self

Converts to this type from the input type.

impl PartialEq for ReadPreference

fn eq(&self, other: &ReadPreference) -> 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 Serialize for ReadPreference

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for ReadPreference