Struct BackpressureConfig 

pub struct BackpressureConfig {
    pub max_pending_writes: usize,
    pub max_pending_reads: usize,
}

Backpressure configuration for client request flow control

Prevents unbounded memory growth by limiting pending client requests. When limits are reached, new requests are rejected with RESOURCE_EXHAUSTED error until the system processes existing requests.

Value Semantics

• 0 = unlimited (no backpressure)
• > 0 = maximum pending requests allowed

Tuning Guidelines(only for reference)

• Low memory (< 4GB): 1000-5000
• Medium memory (4-16GB): 5000-20000
• High memory (> 16GB): 20000-50000

Example

[raft.backpressure]
max_pending_writes = 10000
max_pending_reads = 50000

Fields

max_pending_writes: usize

Maximum pending write (propose) requests

Limits the number of client write requests waiting in the leader’s propose buffer. Write requests typically consume more resources (replication, persistence) than reads.

Default: 10000 (0 = unlimited)

max_pending_reads: usize

Maximum pending linearizable read requests

Limits the number of client linearizable read requests waiting in the leader’s read buffer. Read requests can tolerate higher limits as they don’t require replication.

Default: 50000 (0 = unlimited)

Implementations

impl BackpressureConfig

pub fn should_reject_write(&self, current_pending: usize) -> bool

Check if write request should be rejected due to backpressure

Returns true if the current pending count exceeds the limit. When max_pending_writes == 0, always returns false (unlimited).

pub fn should_reject_read(&self, current_pending: usize) -> bool

Check if read request should be rejected due to backpressure

Returns true if the current pending count exceeds the limit. When max_pending_reads == 0, always returns false (unlimited).

Trait Implementations

impl Clone for BackpressureConfig

fn clone(&self) -> BackpressureConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BackpressureConfig

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

Formats the value using the given formatter.

impl Default for BackpressureConfig

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for BackpressureConfig

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for BackpressureConfig

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.