How does sockets (TCP) impact performance or memory usage?

Sockets, specifically TCP sockets, are fundamental for establishing network connections and data transmission in modern applications. However, utilizing TCP sockets can have various impacts on performance and memory usage. Here we discuss some of the key considerations:

Performance Impact

TCP sockets introduce latency due to their connection-oriented nature. Establishing a connection via the TCP handshake can slow down the initial communication. However, once the connection is established, TCP provides reliable, ordered delivery of data, which can enhance performance for prolonged data transmission. On the downside, the constant checking for packet integrity can introduce overhead, especially in high-throughput scenarios.

Memory Usage

TCP sockets require memory resources for the socket itself, as well as for managing connections and buffers. Each active TCP connection consumes memory for its control structures, buffers, and state information. In applications with thousands of concurrent connections, memory usage can become significant. It is essential to consider efficient management of resources, including proper closing of sockets and monitoring of connection states to avoid leaks and performance degradation.

Example Usage of TCP Sockets in PHP

$sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_connect($sock, '127.0.0.1', 8080);
$message = "Hello, Server!";
socket_write($sock, $message, strlen($message));
$response = socket_read($sock, 1024);
socket_close($sock);
echo $response;