在CodeIgniter中，尝试连接到Unable to connect to the database的mssql（远程连接）时出现错误，该错误不会在每次连接时都出现。有时似乎有时不是

这就是为什么如果反复出现连接问题，我无法获取数据并且服务器速度变慢的原因

我的连接配置在这里，

$db['mssql'] = array(
    'dsn'   => '','hostname' => 'IP,port','username' => '********','password' => '********','database' => '********','dbdriver' => 'sqlsrv','dbprefix' => '','pconnect' => FALSE,'db_debug' => (ENVironMENT !== 'production'),'cache_on' => FALSE,'cachedir' => '','char_set' => 'utf8','dbcollat' => 'utf8_general_ci','swap_pre' => '','encrypt' => FALSE,'compress' => FALSE,'stricton' => FALSE,'failover' => array(),'save_queries' => TRUE
);

以及模型中的示例查询；

public function getBanks($accountCode,$currency){
    $this->Mssql = $this->load->database('mssql',TRUE);
    $this->Mssql->select('accountingCode,BankName,BranchCode,BranchName,IbanNo');
    $this->Mssql->from('Bank');
    $this->Mssql->where(array('accountingCode'=>$accountCode,'Curr'=>$currency));
    return $this->Mssql->get()->result();
}

服务器功能： CodeIgniter 3.1，在centos VPS服务器上具有whm / cpanel。

远程Mssql： microsoft SQL Server 2008 R2（SP3），

编辑：有时查询会花费很长时间或超时。但通常需要3-4秒。下面的长期示例

Uptime:  223 seconds
Executable: 
/opt/cpanel/ea-php73/root/usr/sbin/php-fpm
Command Line (often faked in exploits):
php-fpm: pool mydomian_com                         
Network connections by the process (if any):
tcp: centos:35097 -> mssql:1490
Files open by the process (if any):
/dev/null
/var/cpanel/php/sessions/ea- 
php73/ci_session2c2f2a2567083e33da437a984c0c6171352aa8eb