What version were you using?

v1.30.2

What environment was the server running in?

Linux pop-os 6.4.6-76060406-generic #202307241739169531258622.04~4d8f3e9 SMP PREEMPT_DYNAMIC Thu S x86_64 x86_64 x86_64 GNU/Linux

Is this defect reproducible?

Create lot of Key-Value pairs.
Try to print all keys and values with an watcher.

package main

import (
	"context"
	"fmt"
	"time"

	"github.com/nats-io/nats.go"
	"github.com/nats-io/nats.go/jetstream"
)

func main() {
	nc, err := nats.Connect(nats.DefaultURL)
	if err != nil {
		panic(err)
	}

	js, _ := jetstream.New(nc)

	kv, err := js.KeyValue(context.Background(), "data")
	if err != nil {
		panic(err)
	}

	context, _ := context.WithTimeout(context.Background(), 10*time.Minute)

	start := time.Now()
	watcher, err := kv.Watch(context, ">", jetstream.IgnoreDeletes())
	if err != nil {
		panic(err)
	}
	defer watcher.Stop()

	for entry := range watcher.Updates() {
		if entry == nil {
			break
		}

		fmt.Println(string(entry.Value()))
	}
	fmt.Println(time.Since(start))
}

Here is a demo snapshot of a KV stream with ~3million kVs that can be used for testing:

nats://demo.nats.io:4222

rkaufmann@pop-os:~$ nats --context demo object ls discussions_957 
╭──────────────────────────────────────────────────────╮
│                   Bucket Contents                    │
├─────────────────┬────────┬───────────────────────────┤
│ Name            │ Size   │ Time                      │
├─────────────────┼────────┼───────────────────────────┤
│ snapshot.tar.xz │ 62 MiB │ 2023-04-17T16:14:18+02:00 │
│ demo.go         │ 611 B  │ 2023-04-17T16:17:24+02:00 │
╰─────────────────┴────────┴───────────────────────────╯

Given the capability you are leveraging, describe your expectation?

I created a context with a Timeout of 10 minutes so i should be able to create the watcher if it does not take longer then 10 minutes.

Given the expectation, what is the defect you are observing?

After 5 seconds the program stops with "context deadline exceeded".