MySQL GET_LOCK函数实现MySQL加锁

GET_LOCK(str,timeout)

Tries to obtain a lock with a name given by the string str, using a timeout of timeout seconds. A negative timeout value means infinite timeout. The lock is exclusive. While held by one session, other sessions cannot obtain a lock of the same name.

  • 尝试使用超时秒数的超时获得一个由字符串str给出的名称的锁。
  • 负超时值意味着无限超时。
  • 锁是独占的。
  • 只能由一个会话持有，其他会话无法获得同名的锁。

参考：https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_get-lock
参考：https://blog.csdn.net/tangtong1/article/details/51792617

shadowsocks服务端快速搭建

Install (centos7)

yum install python-setuptools && easy_install pip
pip install git+https://github.com/shadowsocks/shadowsocks.git@master

Usage

ssserver -p 443 -k password -m aes-256-cfb

To run in the background:

sudo ssserver -p 443 -k password -m aes-256-cfb --user nobody -d start

To stop:

sudo ssserver -d stop

To check the log:

sudo less /var/log/shadowsocks.log

Error while reading line from the server.

环境：php7.1、centos7、redis3.2.11
故障现象：php命令行环境下blpop 的时候是不是出现：blpop Error while reading line from the server.
blpop的等待时间是设置为了15秒
—-

Redis经常出现Error while reading line from the server.

cat /proc/sys/net/ipv4/tcp_timestamps
发现返回1
将其设置为0
echo 0 > /proc/sys/net/ipv4/tcp_timestamps

参考：http://blog.csdn.net/jueshengtianya/article/details/50440696

net.ipv4.tcp_timestamps=0

说明：时间戳可以避免序列号的卷绕。一个1Gbps的链路肯定会遇到以前用过的序列号。时间戳能够让内核接受这种“异常”的数据包。这里需要将其关掉。

值为0（禁用时间戳）

值为1（启用时间戳）

—-

然而进行以上操作以后还是会出现

cURL error 60: SSL certificate problem: unable to get local issuer certificate (see http://curl.haxx.se/libcurl/c/libcurl-errors.html)

CURL证书错误问题正确解决方法

方法1：自己自己下载一个根证书（不推荐）
下载地址：https://github.com/bagder/ca-bundle

// curl_setopt ($ch, CURLOPT_SSL_VERIFYHOST, 0);
// curl_setopt ($ch, CURLOPT_SSL_VERIFYPEER, 0);
# curl_setopt($ch, CURLOPT_CAPATH, __DIR__);
curl_setopt($ch, CURLOPT_CAINFO, __DIR__ . '/ca-bundle.crt');

方法2：自动找到系统里的证书路径（推荐）

# 安装
composer require composer/ca-bundle

# 通过下面方法即可返回证书路径
\Composer\CaBundle\CaBundle::getSystemCaRootBundlePath()

// curl_setopt ($ch, CURLOPT_SSL_VERIFYHOST, 0);
// curl_setopt ($ch, CURLOPT_SSL_VERIFYPEER, 0);
# curl_setopt($ch, CURLOPT_CAPATH, __DIR__);
curl_setopt($ch, CURLOPT_CAINFO, \Composer\CaBundle\CaBundle::getSystemCaRootBundlePath());

GuzzleHttp https证书问题解决

$client = new \GuzzleHttp\Client([
    \GuzzleHttp\RequestOptions::VERIFY => \Composer\CaBundle\CaBundle::getSystemCaRootBundlePath()
]);

Nginx Yum安装（官方）

To set up the yum repository, create the file named /etc/yum.repos.d/nginx.repo with the following contents:

[nginx-stable]
name=nginx stable repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=1
enabled=1
gpgkey=https://nginx.org/keys/nginx_signing.key