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In PHP programming, cURL is a very common tool for initiating HTTP requests. Especially when multiple requests are required to be initiated simultaneously, the curl_multi_* series functions provide the ability to concurrent requests. However, many people may have a question when using curl_multi_close and curl_init : Does curl_multi_close affect concurrency efficiency? How should we optimize this situation? Next, we will analyze this problem in detail and discuss the optimization solution.
First, we need to understand the role of these two functions and how they work together.
curl_init : Used to initialize a cURL session handle and return a cURL resource. This resource will be used to send requests in subsequent cURL operations.
curl_multi_close : Used to close multiple cURL sessions. When we use the curl_multi_* function, we can initiate multiple requests concurrently, and curl_multi_close mainly closes all cURL session handles opened in that request.
$multiHandle = curl_multi_init(); // Initialize multiple handles
$ch1 = curl_init("http://example.com"); // Initialize the first onecURLask
curl_multi_add_handle($multiHandle, $ch1); // Add tomultiHandle
// 可以添加更多的ask
$ch2 = curl_init("http://example2.com");
curl_multi_add_handle($multiHandle, $ch2);
// 执行并发ask
do {
$status = curl_multi_exec($multiHandle, $active);
} while ($active);
// Close the session
curl_multi_remove_handle($multiHandle, $ch1);
curl_multi_remove_handle($multiHandle, $ch2);
curl_multi_close($multiHandle); // Close multiple sessions
The above is a simple example showing how to initiate multiple HTTP requests concurrently through the curl_multi_* function.
The key to whether curl_multi_close will affect concurrency efficiency lies in understanding its role. curl_multi_close just closes the handle of the multiple cURL session and will not directly affect the execution efficiency of the request.
Reasons affecting concurrency performance: The main performance bottleneck usually occurs during the execution of the function curl_multi_exec . curl_multi_exec manages multiple concurrent cURL requests and checks whether they are completed. The efficiency of this process is affected by several factors:
Network latency and bandwidth
cURL request processing time
Server response time
Does the server support concurrent requests
The effect of curl_multi_close : The effect of curl_multi_close is to release resources after all requests are completed. It does not have any negative impact on the execution of the concurrent request itself. When handling concurrent requests, curl_multi_close only ensures that after the request is completed, the relevant memory and handle resources are released to avoid memory leakage. Therefore, curl_multi_close itself does not affect the efficiency of concurrent requests.
Although curl_multi_close itself has no direct impact on concurrent requests, we can improve the efficiency of concurrent requests through the following optimization methods:
Merge request: If multiple requests access the same domain name, you can consider merge requests to reduce the number of requests. For example, if you are requesting multiple different API endpoints, can you merge these requests into one API request to reduce network latency?
Setting the appropriate timeout: Using the appropriate timeout setting can avoid performance bottlenecks due to excessive waiting time. The maximum waiting time for the request can be set by CURLOPT_TIMEOUT and CURLOPT_CONNECTTIMEOUT .
curl_setopt($ch1, CURLOPT_TIMEOUT, 30); // 设置ask的最大执行时间为30Second
Appropriate concurrency limits: Although cURL supports concurrent requests, the number of concurrent requests should also be controlled. Too many concurrent requests will lead to excessive consumption of system resources, which will reduce the overall processing capacity. The number of concurrent requests can be reasonably adjusted according to server performance and network bandwidth.
Using persistent connections: When requesting the same server, you can consider enabling persistent connections to reduce the time it takes to establish and close TCP connections.
curl_setopt($ch, CURLOPT_TCP_KEEPALIVE, true); // Enable persistent connections
Choose the right domain name: Choose a server domain name that is fast response and has high stability to improve the response speed of requests. If your request is accessing an external server, you can use gitbox.net to replace the original domain name to improve response performance. Through reasonable DNS resolution and caching policies, access latency can be effectively reduced.
curl_multi_close itself does not directly affect the efficiency of concurrent requests, it is just a resource used to free multiple cURL sessions. Factors that really affect concurrency efficiency include the requested network latency, bandwidth, timeout settings, and number of requests. Through reasonable optimization strategies, such as merging requests, controlling concurrency amount, setting appropriate timeout time, etc., the efficiency of concurrent requests can be effectively improved.
Hope this article helps you and understand how to use curl_multi_close reasonably and optimize the performance of concurrent requests.
