Php-random occurrence of PHPWarning: mysql_connect ()

! After refresh, the page can be opened normally. This may happen again later. on average, about 20 pieces of data are inserted (insertupdate) per second on the website. This problem may occur during peak website access periods. I don't know which optimization can solve this problem? [Environment introduction] System: Server2003MySQL: mysql-5.1.51-win32PHP: 5.4.37ntswebse..phpconnect

After refresh, the page can be opened normally. This may happen again later. on average, about 20 pieces of data are inserted (insert update) per second on the website.

This problem may occur during peak website access periods. I don't know which optimization can solve this problem?

[Environment introduction]
System: Server2003
MySQL: mysql-5.1.51-win32
PHP: 5.4.37 NT
WebServer: IIS6.0 + FastCGI1.5

[Hardware environment]
CPU: Xeon L5520 @ 2.27 GHz
Memory: 8 GB

[I have tried the following solutions but cannot solve them]
1. innodb and MyISAM tables have been tried.
2. modify the value of max_connections to 2048.

Have you ever encountered a similar situation? Please do not give me any further advice.