我们使用 AWS Lambda (Java) 和 elasticsearch 客户端连接到 AWS 上的托管 elasticsearch 实例。我在第一个请求上遇到了大约 2.5 秒的长时间等待(在冷启动之上)。之后它非常快。我真的无法弄清楚这种延迟是从哪里来的，我正在尝试对其进行优化。

private void testPerformanceElasticSearch() throws Exception {
        log.info("1. Before testing elasticsearch client");
        AWS4Signer signer = new AWS4Signer();
        signer.setServiceName("es");
        signer.setRegionName("eu-west-1");
        HttpRequestInterceptor interceptor = new AWSRequestSigningApacheInterceptor("es", signer, new DefaultAWSCredentialsProviderChain());
        String endpoint = "https://" + Utils.getEnvironmentVariable("ELASTIC_SEARCH_ENDPOINT");
        RestHighLevelClient restHighLevelClient = new RestHighLevelClient(RestClient.builder(HttpHost.create(endpoint)).setHttpClientConfigCallback(hacb -> hacb.addInterceptorLast(interceptor)));
        log.info("2. After getting elasticsearch client");
        log.info("3. Before doing a elasticsearch query");
        log.info("4");
        BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
        log.info("5");
        TermsQueryBuilder termsQueryBuilder = QueryBuilders.termsQuery("userId", "abc");
        log.info("6");
        boolQueryBuilder.must(termsQueryBuilder);
        log.info("7");
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        log.info("8");
        searchSourceBuilder.query(boolQueryBuilder);
        log.info("9");
        SearchRequest searchRequest = new SearchRequest("users");
        log.info("10");
        searchRequest.source(searchSourceBuilder);
        log.info("11");
        restHighLevelClient.search(searchRequest);
        log.info("12");
        log.info("13. After testing elasticsearch");
}

然后我像这样记录日志；您可以看到在“5”和“6”之间有超过 2 秒的延迟，我无法确定:

17:16:06.871INFO[PlacesPerformance] 1. Before testing elasticsearch client
17:16:06.932INFO[PlacesPerformance] 2. After getting elasticsearch client
17:16:06.933INFO[PlacesPerformance] 3. Before doing a elasticsearch query
17:16:06.935INFO[PlacesPerformance] 4
17:16:06.942INFO[PlacesPerformance] 5
17:16:09.179INFO[PlacesPerformance] 6
17:16:09.179INFO[PlacesPerformance] 7
17:16:09.181INFO[PlacesPerformance] 8
17:16:09.181INFO[PlacesPerformance] 9
17:16:09.183INFO[PlacesPerformance] 10
17:16:09.183INFO[PlacesPerformance] 11
17:16:09.362INFO[PlacesPerformance] 12
17:16:09.362INFO[PlacesPerformance] 13. After testing elasticsearch

有什么改进建议吗？

更新:

奇怪。每当我在 lambda 中运行代码时，在构建请求(甚至不执行它)时都会遇到 2.5 秒的延迟。在本地，它工作正常。我尝试了以下方法:

1.  Local against local elasticsearch. No delay.
2.  Local against AWS elasticsearch. No delay.
3.  Lambda with signing request. DELAY.
4.  Lambda without signing request. DELAY.
5.  Lambda with a 'match all' query. DELAY
6.  Lambda with a http address. DELAY.
7.  Lambda with a custom runtime. DELAY.
8.  Lambda with a custom runtime. DELAY.
9.  Lambda with standard Java 8 runtime. DELAY.

最佳答案

问题是在第一次请求时(真正的请求，而不是预热请求，因为预热请求不会通过您的应用程序代码，它不会触发实际请求路径中使用的加载类)JVM 加载(阅读，解析、验证等...)相关类，初始化安全组件(密码等...)并完成 TLS 握手(需要多个 RTT，对于 Java 9 和 TLS 1.3 这应该减少)。

对于首次 AWS 服务调用(DynamoDB、SQS 等...)也可以看到类似的长时间行为

因为我是 Thundra 预热插件的作者，我正在考虑为预热消息引入 Hook 点，因为自定义操作将能够执行，如初始化安全组件、加载类等......

关于java - AWS/Lambda/Java 上的 Elasticsearch 客户端 - 2.5 秒客户端启动时间，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/54987470/