php-randomly appearing PHP warning:mysql_connect ()

Phpconnect

After re-refresh the page can be opened normally again, after a while it may occur again, the website average 20 data per second in the Insert (insert Update) data.

This problem occurs during peak site visit, do not know which aspects of optimization can solve the problem?

"Introduction to the Environment"
system:server2003
Mysql:mysql-5.1.51-win32
php:5.4.37 NTS
webserver:iis6.0+fastcgi1.5

"Hardware Environment"
Cpu:xeon L5520 @ 2.27GHz
Memory: 8GB

"I tried the following, but I couldn't fix it."
1, InnoDB types and MyISAM types of tables have been tried.
2, modify the Max_connections to 2048.

May I ask whether you have encountered a similar situation? Please do not hesitate to enlighten me.

