Benchmark JS meta snapshots

Signed-off-by: Maurice van Veen <github@mauricevanveen.com>

Author: MauriceVanVeen

server/jetstream_benchmark_test.go

@@ -18,7 +18,9 @@ package server
 import (
 	"encoding/json"
 	"fmt"
+	"math"
 	"math/rand"
+	"strconv"
 	"sync"
 	"sync/atomic"
 	"testing"
@@ -991,6 +993,88 @@ func BenchmarkJetStreamPublish(b *testing.B) {
 	}
 }
 
+func BenchmarkJetStreamMetaSnapshot(b *testing.B) {
+	c := createJetStreamClusterExplicit(b, "R3S", 3)
+	defer c.shutdown()
+
+	setup := func(reqLevel string) *jetStream {
+		ml := c.leader()
+		acc, js := ml.globalAccount(), ml.getJetStream()
+		n := js.getMetaGroup()
+
+		// Create all streams and consumers.
+		numStreams := 200
+		numConsumers := 500
+		ci := &ClientInfo{Cluster: "R3S", Account: globalAccountName}
+		js.mu.Lock()
+		metadata := map[string]string{JSRequiredLevelMetadataKey: reqLevel}
+		for i := 0; i < numStreams; i++ {
+			scfg := &StreamConfig{
+				Name:     fmt.Sprintf("STREAM-%d", i),
+				Subjects: []string{fmt.Sprintf("SUBJECT-%d", i)},
+				Metadata: metadata,
+			}
+			cfg, _ := ml.checkStreamCfg(scfg, acc, false)
+			rg, _ := js.createGroupForStream(ci, &cfg)
+			sa := &streamAssignment{Group: rg, Sync: syncSubjForStream(), Config: &cfg, Client: ci, Created: time.Now().UTC()}
+			n.Propose(encodeAddStreamAssignment(sa))
+
+			for j := 0; j < numConsumers; j++ {
+				ccfg := &ConsumerConfig{
+					Durable:  fmt.Sprintf("CONSUMER-%d", j),
+					Metadata: metadata,
+				}
+				selectedLimits, _, _, _ := acc.selectLimits(ccfg.replicas(&cfg))
+				srvLim := &ml.getOpts().JetStreamLimits
+				setConsumerConfigDefaults(ccfg, &cfg, srvLim, selectedLimits, false)
+				rg = js.cluster.createGroupForConsumer(ccfg, sa)
+				ca := &consumerAssignment{Group: rg, Stream: cfg.Name, Name: ccfg.Durable, Config: ccfg, Client: ci, Created: time.Now().UTC()}
+				n.Propose(encodeAddConsumerAssignment(ca))
+			}
+		}
+		js.mu.Unlock()
+
+		// Wait for all servers to have created all assets.
+		checkFor(b, 20*time.Second, 200*time.Millisecond, func() error {
+			for _, s := range c.servers {
+				sjs := s.getJetStream()
+				sjs.mu.RLock()
+				streams := sjs.cluster.streams[globalAccountName]
+				if len(streams) != numStreams {
+					sjs.mu.RUnlock()
+					return fmt.Errorf("expected %d streams, got %d", numStreams, len(streams))
+				}
+				for _, sa := range streams {
+					if nc := len(sa.consumers); nc != numConsumers {
+						sjs.mu.RUnlock()
+						return fmt.Errorf("expected %d consumers, got %d", numConsumers, nc)
+					}
+				}
+				sjs.mu.RUnlock()
+			}
+			return nil
+		})
+		return js
+	}
+
+	for _, t := range []struct {
+		title    string
+		reqLevel string
+	}{
+		{title: "Default", reqLevel: "0"},
+		{title: "AllUnsupported", reqLevel: strconv.Itoa(math.MaxInt)},
+	} {
+		b.Run(t.title, func(b *testing.B) {
+			js := setup(t.reqLevel)
+			b.ResetTimer()
+			for range b.N {
+				js.metaSnapshot()
+			}
+			b.StopTimer()
+		})
+	}
+}
+
 func BenchmarkJetStreamCounters(b *testing.B) {
 	const (
 		verbose    = false