perf: index routing snapshots and quota usage

internal/store/benchmark_test.go

@@ -0,0 +1,60 @@
+package store
+
+import (
+	"encoding/json"
+	"fmt"
+	"orchestra/internal/authz"
+	"orchestra/internal/domain"
+	"sort"
+	"testing"
+	"time"
+)
+
+// Append includes the fsynced event-log write and sparse projection-cache
+// checkpoint. The budgets catch accidental return to an O(tasks) snapshot
+// rewrite on every event while remaining practical on CI-backed storage.
+const (
+	appendP95Budget1K  = 10 * time.Second
+	appendP95Budget10K = 90 * time.Second
+)
+
+func BenchmarkAppend1K(b *testing.B)  { benchmarkAppend(b, 1_000, appendP95Budget1K) }
+func BenchmarkAppend10K(b *testing.B) { benchmarkAppend(b, 10_000, appendP95Budget10K) }
+
+func benchmarkAppend(b *testing.B, events int, budget time.Duration) {
+	b.Helper()
+	samples := make([]time.Duration, 0, b.N)
+	b.ResetTimer()
+	for sample := 0; sample < b.N; sample++ {
+		b.StopTimer()
+		s, err := Open(b.TempDir())
+		if err != nil {
+			b.Fatal(err)
+		}
+		b.StartTimer()
+		started := time.Now()
+		for i := 0; i < events; i++ {
+			id := fmt.Sprintf("task-%d", i)
+			payload, _ := json.Marshal(map[string]any{"source": "benchmark", "external_id": id, "project": "p"})
+			if err := s.Append(domain.Event{ID: id, Type: "TaskCreated", TaskID: id, Version: 1, Payload: payload, Surface: string(authz.System)}); err != nil {
+				b.Fatal(err)
+			}
+		}
+		samples = append(samples, time.Since(started))
+		b.StopTimer()
+	}
+	p95 := appendDurationP95(samples)
+	b.ReportMetric(float64(p95.Microseconds()), "append_p95_us")
+	if p95 > budget {
+		b.Fatalf("append p95 %s exceeds budget %s for %d events", p95, budget, events)
+	}
+}
+
+func appendDurationP95(samples []time.Duration) time.Duration {
+	if len(samples) == 0 {
+		return 0
+	}
+	sorted := append([]time.Duration(nil), samples...)
+	sort.Slice(sorted, func(i, j int) bool { return sorted[i] < sorted[j] })
+	return sorted[(len(sorted)*95+99)/100-1]
+}