Enum BackpressureStrategy 

pub enum BackpressureStrategy {
    Block,
    DropOldest,
    DropNewest,
    Buffer {
        max_bytes: usize,
    },
    Sample {
        rate: u32,
    },
}

Strategy applied when the Ring 0 channel is full and cannot accept more messages.

WebSocket sources produce data at the rate of the remote sender. When the downstream processing pipeline cannot keep up, one of these strategies governs how the connector handles the overflow.

Implementation status (2026-03-07):

• Block: fully implemented (TCP backpressure propagation)
• DropNewest: implemented in source.rs via try_send
• DropOldest, Buffer, Sample: parsed from SQL WITH, fall back to DropNewest behavior with a debug log. Full dispatch planned for Phase 6c.

Variants

Block

Block WS read – TCP backpressure propagates to sender.

This is the safest option: the WebSocket read loop simply stops reading, which causes the TCP window to fill, eventually slowing the remote sender. No data is lost, but latency increases.

DropOldest

Drop oldest messages from bounded channel when full.

The channel evicts the oldest buffered message to make room for each new arrival. Good for “latest value wins” use cases.

DropNewest

Drop incoming message when channel full (don’t enqueue).

The newly arriving message is silently discarded. Useful when freshness of already-buffered data matters more than completeness.

Buffer

Buffer up to max_bytes, then drop oldest.

An intermediate strategy: an additional byte-bounded buffer sits in front of the channel. Once the buffer exceeds max_bytes, the oldest buffered messages are evicted.

Fields

max_bytes: usize

Maximum buffer size in bytes before eviction kicks in.

Sample

Sample: keep every Nth message.

Under sustained backpressure, only every rate-th message is forwarded. All others are dropped. Useful for high-frequency telemetry where statistical sampling is acceptable.

Fields

rate: u32

Keep every Nth message (e.g., rate = 10 keeps 10% of messages).

Trait Implementations

impl Clone for BackpressureStrategy

fn clone(&self) -> BackpressureStrategy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BackpressureStrategy

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

Formats the value using the given formatter.

impl Default for BackpressureStrategy

fn default() -> BackpressureStrategy

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for BackpressureStrategy

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for BackpressureStrategy

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

where __S: Serializer,

Serialize this value into the given Serde serializer.