安装依赖
代码语言：javascript复制sudo apt install gcc
sudo apt install g
sudo apt install cmake
sudo apt install libhiredis-dev
sudo apt install libssl-dev安装redis
代码语言：javascript复制git clone https://github.com/sewenew/redis-plus-plus.git
cd redis-plus-plus
mkdir build
cd build
cmake ..
make
sudo make install
cd ..代码
代码语言：javascript复制#include <iostream>
#include <thread>
#include <sw/redis /redis .h>
#include <sw/redis /connection.h>
#include <sw/redis /connection_pool.h>
using namespace sw::redis;
void test_multithreads(Redis redis, int thread_num, int times) {
std::vector<std::string> keys;
keys.reserve(thread_num);
for (auto idx = 0; idx != thread_num; idx) {
auto key = "multi-threads::" std::to_string(idx);
keys.push_back(key);
redis.set(key, key);
}
std::vector<std::thread> workers;
workers.reserve(thread_num);
for (const auto &key : keys) {
workers.emplace_back([&redis, key, times]() {
try {
for (auto i = 0; i != times; i) {
auto val = redis.get(key);
if (!val) {
std::cout<< "failed to test multithreads, cannot get value of " key << std::endl;
return;
}
}
} catch (std::exception &e) {
std::cerr<< "failed to test multithreads, " << e.what() << std::endl;
return;
}
});
}
for (auto &worker : workers) {
worker.join();
}
}
int main() {
ConnectionOptions opts;
opts.host = "127.0.0.1";
opts.port = 6379;
opts.socket_timeout = std::chrono::milliseconds(50);
opts.keep_alive = true;
ConnectionPoolOptions pool_opts;
pool_opts.size = 300;
auto thread_num = 500;
auto times_in_one_second = 1000000;
test_multithreads(Redis(opts, pool_opts), thread_num, times_in_one_second);
}上面代码启动了500个线程，它们公用一个redis连接池。该池子上限被设置为300个。每个线程内部会查询1000000次，以维持程序运行，让我们可以观察到中间连接数变化。 使用下面的脚本进行编译
代码语言：javascript复制g -std=c 17 -o main main.cpp /usr/local/lib/libredis .a /usr/lib/x86_64-linux-gnu/libhiredis.a -pthread查看连接数
使用下面命令进入交互界面
代码语言：javascript复制redis-cli -h 127.0.0.1 -p 6379然后使用下面命令查看连接数，connected_clients为1，即当前redis-cli的连接。
代码语言：javascript复制info clients# Clients connected_clients:1 client_recent_max_input_buffer:8 client_recent_max_output_buffer:0 blocked_clients:0 tracking_clients:0 clients_in_timeout_table:0
在一个新窗口中运行上面编译的测试程序。
代码语言：javascript复制./main 然后再查看连接数
# Clients connected_clients:301 client_recent_max_input_buffer:8 client_recent_max_output_buffer:0 blocked_clients:0 tracking_clients:0 clients_in_timeout_table:0
可以看到连接数增加了300。这个和我们代码中设置的连接池大小上限匹配。
参考资料
- https://github.com/sewenew/redis-plus-plus/tree/master
