Module query_telemetry 

Per-Query Telemetry (Task 10)

Structured telemetry for every query to enable:

• Optimization: falsifiable hypotheses about performance
• Regression detection: automatic SLA monitoring
• Explainability: “why was this query slow?”

Metrics Captured

• Routing: time, lists considered/scanned
• Scan: codes evaluated, RAM bytes read
• Rerank: candidates, SSD ops/bytes
• Cache: hit ratio
• Error: estimated ε envelope used
• Stop: termination mode and reason

Usage

use sochdb_vector::query_telemetry::{QueryTelemetry, TelemetryCollector};

let mut telemetry = QueryTelemetry::new("search_v1");
telemetry.record_routing(Duration::from_micros(500), 100, 16);
telemetry.record_scan(1024, 16 * 1024 * 1024);
telemetry.set_stop_reason(StopReason::BoundSatisfied);

// Emit structured telemetry
let json = telemetry.to_json();

Structs

CacheMetrics

Cache metrics

CostSummaryJson

JSON-serializable cost summary

ErrorEnvelopeMetrics

Error envelope metrics

QueryTelemetry

Comprehensive per-query telemetry

RerankMetrics

Rerank phase metrics

RoutingMetrics

Routing phase metrics

ScanMetrics

Scan phase metrics

TelemetryAggregate

Aggregate telemetry statistics

TelemetryCollector

Thread-safe telemetry collector with aggregation

TerminationMetrics

Termination metrics

Enums

CacheType

Cache type for hit/miss tracking