在Ubuntu系统中测试Redis连接池——redis++方案

安装依赖

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++

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

#include 
#include 
#include 
#include 
#include 
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

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

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。

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。

./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