目前使用MySQL的网站,多半同时使用Memcache作为键值缓存。虽然这样的架构极其流行,有众多成功的案例,但过于依赖Memcache,无形中让Memcache成为故障的根源:
Memcache数据一致性的问题:当MySQL数据变化后,如果不能及时有效的清理掉过期的数据,就会造成数据不一致。这在强调即时性的Web2.0时代,不可取。
Memcache崩溃后的雪崩效应:作为缓存的Memcache一旦崩溃,MySQL很可能在短时间内承受高负载而宕机。
注:关于清理过期数据的问题,可以在程序架构上想办法,如果数据操作有统一DAO封装的话,可以利用Observer模式来清理过期数据,非主题内容,资料自查。
面对以上问题,HandlerSocket项目是个不错的解决方案,它通过插件的方式赋予MySQL完整的NoSQL功能,从原理上讲,它跳过MySQL中最耗时的语法解析,查询计划等步骤,直接读取数据,如果内存够大,能装下索引,MySQL的查询效率能提高若干倍!
HandlerSocket:https://github.com/ahiguti/HandlerSocket-Plugin-for-MySQL
php-handlersocket:http://code.google.com/p/php-handlersocket/
系统信息约定:
系统版本:CentOS 6.3 X86
PHP安装目录:/usr/local/webserver/php5318
MySQL安装目录:/usr/local/webserver/mysql5520
HandlerSocket安装路径:/usr/local/webserver/handlersocket
二、安装配置HandlerSocket
安装之前建议你先安装相关支持及需要的组件包:
yum install gcc gcc-c++ libtool make openssl-devel perl-DBI perl-DBD-MySQL
yum install rpm-build gperf readline-devel ncurses-devel time perl-Time-HiRes
1. 安装
如果使用Percona Server版本的MySQL就简单了,因为它已经内置了HandlerSocket支持,不过考虑到其内置的版本不够新,存在一些早已修复的BUG,所以最好采用源代码编译。HandlerSocket是基于MySQL数据库的,因此在安装HanderSocket前需要先按照常规方式部署MySQL服务,同时需注意HandlerSocket时需要MySQL的源码,因此还需要MySQL源码编译方式安装。
[root@iredmail opt]# git clone https://github.com/ahiguti/HandlerSocket-Plugin-for-MySQL.git
[root@iredmail opt]# cd HandlerSocket-Plugin-for-MySQL
[root@iredmail HandlerSocket-Plugin-for-MySQL]# ./autogen.sh
[root@iredmail HandlerSocket-Plugin-for-MySQL]#./configure --prefix=/usr/local/webserver/handlersocket --with-mysql-source=/opt/mysql-5.5.20 --with-mysql-bindir=/usr/local/webserver/mysql5520/bin --with-mysql-plugindir=/usr/local/webserver/mysql5520/lib/mysql/plugin
Tips:
--with-mysql-source 指定MySQL源码所在目录
--with-mysql-bindir 表示MySQL二进制可执行文件目录
--with-mysql-plugindir 指定MySQL插件的存储路径,如果不清楚这个目录在哪,可以按如下方法查询:
mysql> show variables like 'plugin%';
+---------------+-------------------------------------------+
| Variable_name | Value |
+---------------+-------------------------------------------+
| plugin_dir | /usr/local/webserver/mysql5520/lib/plugin |
+---------------+-------------------------------------------+
1 row in set (0.00 sec)
[root@iredmail HandlerSocket-Plugin-for-MySQL]# make
常见错误:
libtool: link: only absolute run-paths are allowed
make[2]: *** [handlersocket.la] Error 1
make[2]: Leaving directory `/opt/HandlerSocket-Plugin-for-MySQL/handlersocket'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/opt/HandlerSocket-Plugin-for-MySQL'
make: *** [all] Error 2
解决方法:
[root@iredmail HandlerSocket-Plugin-for-MySQL]# vi handlersocket/Makefile
line 301:
$(handlersocket_la_LINK) -rpath $(pkgplugindir) $(handlersocket_la_OBJECTS) $(handlersocket_la_LIBADD) $(LIBS)
-->
$(handlersocket_la_LINK) -rpath /opt/HandlerSocket-Plugin-for-MySQL/handlersocket $( handlersocket_la_OBJECTS) $(handlersocket_la_LIBADD) $(LIBS)
[root@iredmail HandlerSocket-Plugin-for-MySQL]#make install
完成后,mysql-plugindir目录下应有handlersocket相关文件
2、配置MySQL:
修改my.cnf配置文件:
[root@iredmail HandlerSocket-Plugin-for-MySQL]# vi /etc/my.cnf
[mysqld]
plugin-load=handlersocket.so(plugin-load可略过不配)
loose_handlersocket_port = 9998 # 指定读请求端口号
# the port number to bind to (for read requests)
loose_handlersocket_port_wr = 9999 # 指定写请求端口号
# the port number to bind to (for write requests)
loose_handlersocket_threads = 16 # 指定读线程数目
# the number of worker threads (for read requests)
loose_handlersocket_threads_wr = 1 # 指定写线程数目
# the number of worker threads (for write requests)
open_files_limit = 65535
# to allow handlersocket accept many concurren connections, make open_files_limit as large as possible.
Tips:InnoDB的innodb_buffer_pool_size,或MyISAM的key_buffy_size等关系到缓存索引的选项尽可能设置大一些,这样才能发挥HandlerSocket的潜力。
登陆MySQL并激活HandlerSocket插件:
[root@iredmail HandlerSocket-Plugin-for-MySQL]# mysql -uroot -p
mysql> install plugin handlersocket soname 'handlersocket.so';
ERROR 1126 (HY000): Can't open shared library '/usr/local/webserver/mysql5520/lib/plugin/handlersocket.so' (errno: 2 cannot open shared object file: No such file or directory)
说明:这里提示没有找到handlersocket.so扩展文件,请查看扩展文件是否存在。
mysql> install plugin handlersocket soname 'handlersocket.so';
Query OK, 0 rows affected (0.00 sec)
mysql> quit;
至此,HandlerSocket插件安装完毕。
重启mysql服务:
[root@iredmail HandlerSocket-Plugin-for-MySQL]# service mysqld restart
3、HandlerSocket状态测试:
Tips:If ports 9998 and 9999 don't show up. Make sure SELinux is not running.
三、安装配置 php-handlersocket 扩展模块:
1、安装php-handlersocket扩展
[root@iredmail opt]# wget http://php-handlersocket.googlecode.com/files/php-handlersocket-0.3.1.tar.gz
[root@iredmail opt]# tar -zxvf php-handlersocket-0.3.1.tar.gz
[root@iredmail opt]# cd handlersocket/
[root@iredmail handlersocket]# /usr/local/webserver/php5318/bin/phpize
[root@iredmail handlersocket]# ./configure --with-php-config=/usr/local/webserver/php5318/bin/php-config
./configure可加参数:
至此php扩展安装完成,放问php.info页面,我们可以看到已经成功加载了handlersocket扩展
Example:
测试库 hstestdb,测试表hstesttbl:
CREATE TABLE `hstesttbl` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`k` char(6) DEFAULT NULL,
`v` char(6) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `idx_hstesttbl_k` (`k`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;
PHP Test Code:
$host = 'localhost';
$port = 9998;
$port_wr = 9999;
$dbname = 'hstestdb';
$table = 'hstesttbl';
//GET
$hs = new HandlerSocket($host, $port);
if (!($hs->openIndex(1, $dbname, $table, HandlerSocket::PRIMARY, 'k,v'))) {
echo $hs->getError(), PHP_EOL;
die();
}
$retval = $hs->executeSingle(1, '=', array('k1'), 1, 0);
var_dump($retval);
$retval = $hs->executeMulti(
array(
array(1, '=', array('k1'), 1, 0),
array(1, '=', array('k2'), 1, 0)
)
);
var_dump($retval);
unset($hs);
//UPDATE
$hs = new HandlerSocket($host, $port_wr);
if (!($hs->openIndex(2, $dbname, $table, '', 'v'))) {
echo $hs->getError(), PHP_EOL;
die();
}
if ($hs->executeUpdate(2, '=', array('k1'), array('V1'), 1, 0) === false) {
echo $hs->getError(), PHP_EOL;
die();
}
unset($hs);
//INSERT
$hs = new HandlerSocket($host, $port_wr);
if (!($hs->openIndex(3, $dbname, $table, '', 'k,v'))) {
echo $hs->getError(), PHP_EOL;
die();
}
if ($hs->executeInsert(3, array('k2', 'v2')) === false) {
echo $hs->getError(), PHP_EOL;
}
if ($hs->executeInsert(3, array('k3', 'v3')) === false) {
echo 'A', $hs->getError(), PHP_EOL;
}
if ($hs->executeInsert(3, array('k4', 'v4')) === false) {
echo 'B', $hs->getError(), PHP_EOL;
}
unset($hs);
//DELETE
$hs = new HandlerSocket($host, $port_wr);
if (!($hs->openIndex(4, $dbname, $table, '', ''))) {
echo $hs->getError(), PHP_EOL;
die();
}
if ($hs->executeDelete(4, '=', array('k2')) === false) {
echo $hs->getError(), PHP_EOL;
die();
}
?>
Tips:理论上HandlerSocket支持MyISAM,InnoDB等各种引擎,不过推荐使用InnoDB。
Tips:To avoid the insert error,Please remember set storage engine:InnoDB.
Tips:对HandlerSocket一个常见的误解是只能执行PRIMARY类型的KV查询,实际上只要支持索引,一般的简单查询它都能胜任,这里就不多说了,官方文档 里有介绍。
HandlerSocket的缺陷:
(1)写操作并没有淘汰查询缓存――如果执行了写操作通过HandlerSocket,由于没有失效查询缓存, 那么你可能从MySQL读到旧的数据;
(2)不支持自动递增――插入时无法从自增列上自动获得增量值。
鉴于以上问题,扬长避短,使用其合并查询操作,发挥其NoSQL性能获取MySQL的InnoDB类型表数据,具体操作如下:
// 通过handlersocket获取数据
$hs = new HandlerSocket(HS_HOST, HS_PORT);
if (!($hs->openIndex(1, 'dbname', 'table', HandlerSocket::PRIMARY, 'id,content,create_uid,create_user,created,state'))){
echo $hs->getError(), PHP_EOL;
die();
}
$dataList = array();
foreach ($ids as $id) {
$dataList[] = array(1, "=", array($id));
}
$data = $hs->executeMulti($dataList);
写在最后的:
MySQL5.6提供原生的Memcached API,实际就是KV型NoSQL了,但HandlerSocket并不局限于KV形式,所以仍然有生存空间。