安装依赖
bash
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++
bash
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
cpp
#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
bash
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
bash
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。
bash
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。
bash
./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。