I have a simple program which is keep reading the same key from the redis (installed on my machine). My main goal was to compare the virtual thread and WebFlux. I found that WebFlux which is using Lettuce gives issue as I increase the load (using Artillery).

{
      "min": 4,
      "max": 1241,
      "count": 735,
      "mean": 505.9,
      "p50": 518.1,
      "median": 518.1,
      "p75": 820.7,
      "p90": 1064.4,
      "p95": 1153.1,
      "p99": 1224.4,
      "p999": 1249.1
    }

while the VT (using Spring MVC) takes few milliseconds (as expected) to complete the load. It looks like something is blocking/queuing up here. My code looks pretty simple as shown below

@GetMapping(value = "/{testName}", produces = MediaType.APPLICATION_JSON_VALUE)
public Mono<Test> getTest(@PathVariable String testName) {
    return testService.getCachedTest(testName)
            .log();
}

The RedisConfig looks like below

@Configuration

public class RedisConfig {

@Bean
public ReactiveRedisOperations<String, Test> redisOperations(ReactiveRedisConnectionFactory reactiveRedisConnectionFactory) {
    Jackson2JsonRedisSerializer<Test> serializer = new Jackson2JsonRedisSerializer<>(Test.class);

    RedisSerializationContext.RedisSerializationContextBuilder<String, Test> builder =
            RedisSerializationContext.newSerializationContext(new Jackson2JsonRedisSerializer<>(Test.class));

    RedisSerializationContext<String, Test> context =
            builder
                    .key(new StringRedisSerializer())
                    .value(serializer)
                    .build();

    return new ReactiveRedisTemplate<>(reactiveRedisConnectionFactory, context);
}

}

Can anyone please help to justify the delay (taking more than 1sec for 735 counts)?