how to verify http connection pool can improve performance - httpconnection

Question

I want to use http connection pool with Spring RestTemplate, but before using it, I need to verify whether it can improve performance.
I do a little programing here:
#Configuration
public class RestTemplateConfig {
#Bean
public RestTemplate restTemplate() {
return new RestTemplate();
}
}
and test code here
#SpringBootTest
class RestnopoolApplicationTests {
String url = "https://www.baidu.com/";
// String url = "http://localhost:8080/actuator/";
#Autowired
RestTemplate restTemplate;
#Test
void contextLoads() {
}
#Test
void verify_health() {
Instant start = Instant.now();
for(int i=0; i < 100; i ++) {
restTemplate.getForObject(url, String.class);
}
Instant end = Instant.now();
Duration d = Duration.between(start,end );
System.out.println("time span " + d.getSeconds());
}
Also, I write http connection pool below
import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.util.concurrent.TimeUnit;
import org.apache.http.HeaderElement;
import org.apache.http.HeaderElementIterator;
import org.apache.http.HttpResponse;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.ConnectionKeepAliveStrategy;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.message.BasicHeaderElementIterator;
import org.apache.http.protocol.HTTP;
import org.apache.http.protocol.HttpContext;
import org.apache.http.ssl.SSLContextBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
/**
* - Supports both HTTP and HTTPS
* - Uses a connection pool to re-use connections and save overhead of creating connections.
* - Has a custom connection keep-alive strategy (to apply a default keep-alive if one isn't specified)
* - Starts an idle connection monitor to continuously clean up stale connections.
*/
#Configuration
#EnableScheduling
public class HttpClientConfig {
private static final Logger LOGGER = LoggerFactory.getLogger(HttpClientConfig.class);
// Determines the timeout in milliseconds until a connection is established.
private static final int CONNECT_TIMEOUT = 30000;
// The timeout when requesting a connection from the connection manager.
private static final int REQUEST_TIMEOUT = 30000;
// The timeout for waiting for data
private static final int SOCKET_TIMEOUT = 60000;
private static final int MAX_TOTAL_CONNECTIONS = 50;
private static final int DEFAULT_KEEP_ALIVE_TIME_MILLIS = 20 * 1000;
private static final int CLOSE_IDLE_CONNECTION_WAIT_TIME_SECS = 30;
#Bean
public PoolingHttpClientConnectionManager poolingConnectionManager() {
SSLContextBuilder builder = new SSLContextBuilder();
try {
builder.loadTrustMaterial(null, new TrustSelfSignedStrategy());
} catch (NoSuchAlgorithmException | KeyStoreException e) {
LOGGER.error("Pooling Connection Manager Initialisation failure because of " + e.getMessage(), e);
}
SSLConnectionSocketFactory sslsf = null;
try {
sslsf = new SSLConnectionSocketFactory(builder.build());
} catch (KeyManagementException | NoSuchAlgorithmException e) {
LOGGER.error("Pooling Connection Manager Initialisation failure because of " + e.getMessage(), e);
}
Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder
.<ConnectionSocketFactory>create().register("https", sslsf)
.register("http", new PlainConnectionSocketFactory())
.build();
PoolingHttpClientConnectionManager poolingConnectionManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry);
poolingConnectionManager.setMaxTotal(MAX_TOTAL_CONNECTIONS);
return poolingConnectionManager;
}
#Bean
public ConnectionKeepAliveStrategy connectionKeepAliveStrategy() {
return new ConnectionKeepAliveStrategy() {
#Override
public long getKeepAliveDuration(HttpResponse response, HttpContext context) {
HeaderElementIterator it = new BasicHeaderElementIterator
(response.headerIterator(HTTP.CONN_KEEP_ALIVE));
while (it.hasNext()) {
HeaderElement he = it.nextElement();
String param = he.getName();
String value = he.getValue();
if (value != null && param.equalsIgnoreCase("timeout")) {
return Long.parseLong(value) * 1000;
}
}
return DEFAULT_KEEP_ALIVE_TIME_MILLIS;
}
};
}
#Bean
public CloseableHttpClient httpClient() {
RequestConfig requestConfig = RequestConfig.custom()
.setConnectionRequestTimeout(REQUEST_TIMEOUT)
.setConnectTimeout(CONNECT_TIMEOUT)
.setSocketTimeout(SOCKET_TIMEOUT).build();
return HttpClients.custom()
.setDefaultRequestConfig(requestConfig)
.setConnectionManager(poolingConnectionManager())
.setKeepAliveStrategy(connectionKeepAliveStrategy())
.build();
}
#Bean
public Runnable idleConnectionMonitor(final PoolingHttpClientConnectionManager connectionManager) {
return new Runnable() {
#Override
#Scheduled(fixedDelay = 10000)
public void run() {
try {
if (connectionManager != null) {
LOGGER.trace("run IdleConnectionMonitor - Closing expired and idle connections...");
connectionManager.closeExpiredConnections();
connectionManager.closeIdleConnections(CLOSE_IDLE_CONNECTION_WAIT_TIME_SECS, TimeUnit.SECONDS);
} else {
LOGGER.trace("run IdleConnectionMonitor - Http Client Connection manager is not initialised");
}
} catch (Exception e) {
LOGGER.error("run IdleConnectionMonitor - Exception occurred. msg={}, e={}", e.getMessage(), e);
}
}
};
}
}
and RestTemplateConfig below
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.scheduling.TaskScheduler;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import org.springframework.web.client.RestTemplate;
import org.apache.http.impl.client.CloseableHttpClient;
#Configuration
public class RestTemplateConfig {
#Autowired
CloseableHttpClient httpClient;
#Bean
public RestTemplate restTemplate() {
RestTemplate restTemplate = new RestTemplate(clientHttpRequestFactory());
return restTemplate;
}
#Bean
public HttpComponentsClientHttpRequestFactory clientHttpRequestFactory() {
HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory();
clientHttpRequestFactory.setHttpClient(httpClient);
return clientHttpRequestFactory;
}
#Bean
public TaskScheduler taskScheduler() {
ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
scheduler.setThreadNamePrefix("poolScheduler");
scheduler.setPoolSize(50);
return scheduler;
}
}
The test result cannot prove that connection pool impvoe performance.

Answer 1

You have not used your new implementation. You are still using the default Apache client. Use your method httpClient() to get the ClosableHttpClient.

Answer 2

Please also note that your test is synchronous, no matter how many connections do you have in the pool, you will use it sequential. Use threads to execute the get request.