個人在虛擬機器centos7，單核，1G記憶體
/**
* 模拟并发请求，10万次写入数据库
* 拆分为10个进程，每个进程处理一万条插入
*/
$total = 10000;
$num = 10;
$per = $total/$num;
$sql = '';
$child = '';
echo 'start '.microtime(true).PHP_EOL;
for($i = 1; $i<= $num; $i++)
{
$pid = pcntl_fork();
if($pid == -1) {
die('fork error');
}
if($pid > 0) {
//$id = pcntl_wait($status,WNOHANG);
$child[] = $pid;
} else if ($pid == 0) {
$link = mysqli_connect('localhost','root','root','yii2advanced');
$start = ($i-1)*$per + 1;
$end = $start + $per;
for($j = $start; $j< $end; $j++){
$time = microtime(true);
$sql = 'insert pcntl_test (rank,time) values ('.$j.','.$time.')';
mysqli_query($link,$sql);
}
mysqli_close($link);
$id = getmypid();
echo 'child '.$id.' finished '.microtime(true).PHP_EOL;
exit(0);
}
}
while(count($child)){
foreach($child as $k => $pid) {
$res = pcntl_waitpid($pid, $status, WNOHANG);
if ( -1 == $res || $res > 0) {
unset($child[$k]);
}
}
}
echo 'end '.microtime(true).PHP_EOL;登入後複製
登入後複製
當$total=10000，$num = 10;執行結果如下:
start 1491903371.5548
child 19860 finished 1491903417.2113
child 19857 finished 1491903417.6909
child 19864 finished 1491903417.7793
child 19855 finished 1491903417.8695
child 19859 finished 1491903417.9162
child 19861 finished 1491903418.0089
child 19856 finished 1491903418.0532
child 19863 finished 1491903418.0842
child 19862 finished 1491903418.1474
child 19858 finished 1491903418.4341
end 1491903418.4424
总时间为46.88759994506836秒
登入後複製
登入後複製
當$total=10000,$ num = 100時，執行結果如下：
start 1491904334.1735
child 20085 finished 1491904337.0712
child 20086 finished 1491904337.144
……
child 20262 finished 1491904341.5602
child 20264 finished 1491904341.5803
end 1491904341.5869
总时间为7.413399934768677
登入後複製
登入後複製
當$total=10000,$num = 1000時，執行結果如下：
start 1491904562.0166
child 20282 finished 1491904562.1191
child 20277 finished 1491904562.1268
child 20279 finished 1491904562.1352
...
child 21586 finished 1491904576.6954
child 21582 finished 1491904576.7024
child 21584 finished 1491904576.7226
end 1491904576.7297
总时间为14.71310019493103，相比100个子进程，耗时更长了。进程切换太多，影响了了效率应该是原因之一。
登入後複製
登入後複製
當$total=100000 ,$num=100時，十萬筆記錄，100個進程插入
start 1491905670.2652
child 21647 finished 1491905725.4382
child 21651 finished 1491905725.4595
child 21642 finished 1491905725.5402
....
child 21810 finished 1491905729.7709
child 21812 finished 1491905729.8498
child 21811 finished 1491905729.9612
end 1491905729.9679
总时间为59.70270013809204
登入後複製
登入後複製
單一進程插入1萬個數據，耗時18秒，相對10個進程插入1萬個記錄來說，耗時少一點。
而單進程插入10萬筆記錄，耗時187.40066790581，相對來說，是挺慢的了。三分鐘。 。 。
不過，本人再fork 1000個進程，來插入10萬記錄時，成功的情況下36秒左右，也可能會出現錯誤，mysqli_connection返回false，是不是連線數受限了？
fork 一萬個子進程，插入一百萬個數據，這時，出現連接錯的情況就很多了。最後耗時360秒，在資料表中插入了945,300筆記錄,成功率94.53%。於是查看資料庫的相關設定資訊
mysql> show global status like '%connect%';
+-----------------------------------------------+---------------------+
| Variable_name | Value |
+-----------------------------------------------+---------------------+
| Aborted_connects | 0 |
| Connection_errors_accept | 0 |
| Connection_errors_internal | 0 |
| Connection_errors_max_connections | 628 |
| Connection_errors_peer_address | 0 |
| Connection_errors_select | 0 |
| Connection_errors_tcpwrap | 0 |
| Connections | 16519 |
| Locked_connects | 0 |
| Max_used_connections | 501 |
| Max_used_connections_time | 2017-04-12 15:19:54 |
| Performance_schema_session_connect_attrs_lost | 0 |
| Ssl_client_connects | 0 |
| Ssl_connect_renegotiates | 0 |
| Ssl_finished_connects | 0 |
| Threads_connected | 4 |
+-----------------------------------------------+---------------------+
mysql> show global variables like '%connect%';
+-----------------------------------------------+--------------------+
| Variable_name | Value |
+-----------------------------------------------+--------------------+
| character_set_connection | utf8mb4 |
| collation_connection | utf8mb4_general_ci |
| connect_timeout | 10 |
| disconnect_on_expired_password | ON |
| init_connect | |
| max_connect_errors | 100 |
| max_connections | 500 |
| max_user_connections | 0 |
| performance_schema_session_connect_attrs_size | 512 |
+-----------------------------------------------+--------------------+
修改 myqsql 配置文件，/etc/my.cnf
把max_connections 改为10000，然后重启mysql
实际MySQL服务器允许的最大连接数16384；
结果然并卵，虚拟机好像挂了了。
登入後複製
登入後複製
並發量大的時候，問題就出在連接mysql這裡了。
可以透過一個連線池來嘗試解決該問題。
個人在虛擬機器centos7，單核，1G記憶體
/**
* 模拟并发请求，10万次写入数据库
* 拆分为10个进程，每个进程处理一万条插入
*/
$total = 10000;
$num = 10;
$per = $total/$num;
$sql = '';
$child = '';
echo 'start '.microtime(true).PHP_EOL;
for($i = 1; $i<= $num; $i++)
{
$pid = pcntl_fork();
if($pid == -1) {
die('fork error');
}
if($pid > 0) {
//$id = pcntl_wait($status,WNOHANG);
$child[] = $pid;
} else if ($pid == 0) {
$link = mysqli_connect('localhost','root','root','yii2advanced');
$start = ($i-1)*$per + 1;
$end = $start + $per;
for($j = $start; $j< $end; $j++){
$time = microtime(true);
$sql = 'insert pcntl_test (rank,time) values ('.$j.','.$time.')';
mysqli_query($link,$sql);
}
mysqli_close($link);
$id = getmypid();
echo 'child '.$id.' finished '.microtime(true).PHP_EOL;
exit(0);
}
}
while(count($child)){
foreach($child as $k => $pid) {
$res = pcntl_waitpid($pid, $status, WNOHANG);
if ( -1 == $res || $res > 0) {
unset($child[$k]);
}
}
}
echo 'end '.microtime(true).PHP_EOL;登入後複製
登入後複製
當$total=10000，$num = 10;執行結果如下:
start 1491903371.5548
child 19860 finished 1491903417.2113
child 19857 finished 1491903417.6909
child 19864 finished 1491903417.7793
child 19855 finished 1491903417.8695
child 19859 finished 1491903417.9162
child 19861 finished 1491903418.0089
child 19856 finished 1491903418.0532
child 19863 finished 1491903418.0842
child 19862 finished 1491903418.1474
child 19858 finished 1491903418.4341
end 1491903418.4424
总时间为46.88759994506836秒
登入後複製
登入後複製
當$total= 10000,$num = 100時，執行結果如下：
start 1491904334.1735
child 20085 finished 1491904337.0712
child 20086 finished 1491904337.144
……
child 20262 finished 1491904341.5602
child 20264 finished 1491904341.5803
end 1491904341.5869
总时间为7.413399934768677
登入後複製
登入後複製
當$total=10000,$num = 1000時，執行結果如下：
start 1491904562.0166
child 20282 finished 1491904562.1191
child 20277 finished 1491904562.1268
child 20279 finished 1491904562.1352
...
child 21586 finished 1491904576.6954
child 21582 finished 1491904576.7024
child 21584 finished 1491904576.7226
end 1491904576.7297
总时间为14.71310019493103，相比100个子进程，耗时更长了。进程切换太多，影响了了效率应该是原因之一。
登入後複製
登入後複製
當$total=100000 ,$num =100時，十萬筆記錄，100個進程插入
start 1491905670.2652
child 21647 finished 1491905725.4382
child 21651 finished 1491905725.4595
child 21642 finished 1491905725.5402
....
child 21810 finished 1491905729.7709
child 21812 finished 1491905729.8498
child 21811 finished 1491905729.9612
end 1491905729.9679
总时间为59.70270013809204
登入後複製
登入後複製
單一進程插入1萬筆數據，耗時18秒，相對10個進程插入1萬筆記錄來說，耗時少一點。
而單進程插入10萬筆記錄，耗時187.40066790581，相對來說，是挺慢的了。三分鐘。 。 。
不過，本人再fork 1000個進程，來插入10萬記錄時，成功的情況下36秒左右，也可能會出現錯誤，mysqli_connection返回false，是不是連線數受限了？
fork 一萬個子進程，插入一百萬個數據，這時，出現連接錯的情況就很多了。最後耗時360秒，在資料表中插入了945,300筆記錄,成功率94.53%。於是查看資料庫的相關設定資訊
mysql> show global status like '%connect%';
+-----------------------------------------------+---------------------+
| Variable_name | Value |
+-----------------------------------------------+---------------------+
| Aborted_connects | 0 |
| Connection_errors_accept | 0 |
| Connection_errors_internal | 0 |
| Connection_errors_max_connections | 628 |
| Connection_errors_peer_address | 0 |
| Connection_errors_select | 0 |
| Connection_errors_tcpwrap | 0 |
| Connections | 16519 |
| Locked_connects | 0 |
| Max_used_connections | 501 |
| Max_used_connections_time | 2017-04-12 15:19:54 |
| Performance_schema_session_connect_attrs_lost | 0 |
| Ssl_client_connects | 0 |
| Ssl_connect_renegotiates | 0 |
| Ssl_finished_connects | 0 |
| Threads_connected | 4 |
+-----------------------------------------------+---------------------+
mysql> show global variables like '%connect%';
+-----------------------------------------------+--------------------+
| Variable_name | Value |
+-----------------------------------------------+--------------------+
| character_set_connection | utf8mb4 |
| collation_connection | utf8mb4_general_ci |
| connect_timeout | 10 |
| disconnect_on_expired_password | ON |
| init_connect | |
| max_connect_errors | 100 |
| max_connections | 500 |
| max_user_connections | 0 |
| performance_schema_session_connect_attrs_size | 512 |
+-----------------------------------------------+--------------------+
修改 myqsql 配置文件，/etc/my.cnf
把max_connections 改为10000，然后重启mysql
实际MySQL服务器允许的最大连接数16384；
结果然并卵，虚拟机好像挂了了。
登入後複製
登入後複製
並發量大的時候，問題就出在連接mysql這裡了。
可以透過一個連線池來嘗試解決該問題。
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