I just changed my server and experience these errors below:
Fatal error: Call to undefined function mysqli_init() in /home/blacktwitter/public_html/system/database/drivers/mysqli/mysqli_driver.php on line 126
A PHP Error was encountered
Severity: Warning
Message: Cannot modify header information - headers already sent by (output started at /home/blacktwitter/public_html/system/database/drivers/mysqli/mysqli_driver.php:126)
Filename: core/Common.php
Line Number: 564
Backtrace:
A PHP Error was encountered
Severity: Error
Message: Call to undefined function mysqli_init()
Filename: mysqli/mysqli_driver.php
Line Number: 126
Backtrace:
Website is in Codeigniter. It works on one server very well and on the local machine too. But when I upload that website at the new server I have that errors. Of course I changed important parameters like database connection, base_url() etc.
I was suspicious about database, but I have created a new database and user etc. and changed connection info.
Why does this happen? It will be helpful to know if it is a bug at the server or at the website. Also when I create some index.html with some test code everything is fine.
It is not a bug in your application, it is just a missing driver, so, you have couple of options...
Go to your php init and uncomment the following:
extension=php_mysqli.dll
If not, try installing it at your server, it varies depending on your distribution.
Try installing php5-mysqlnd
If you cannot do it by hosting restrictions then just move to mysql driver (wont need to change other configurations or queries in CodeIgniter or anything else...)
like this (at your config file)
$db['default']['dbdriver'] = 'mysql'; (you might have mysqli now)
I just had this issue on a ubuntu16.04, php7.1 install with Codeigniter 3.
Solution was simple (if hard to find!)
sudo apt-get install php7.0-mysql
I realised that the mysql*.ini files where missing from the etc/php/7.1/mods-available directory. Not sure how it happened, but that worked for me.
If you use 7.2, simply type sudo apt-get install php7.2-mysql
Use this:
sudo apt-get install php7.*-mysqli
or
sudo phpenmod mysqli
sudo service apache2 restart
This is actually not a CodeIgniter issue but PHP installation issue.
I have installed PHP5.6 in my Linux server and is having a hard time following the googled solutions of using the ff command in order to install the missing mysqli_extension in PHP.
What I tried is but is returning the warning message: Unable to locate package php5-mysqli
sudo apt-get install php5-mysqli
However, my php version is 5.6 so I tried
sudo apt-get install php5.6-mysqli
Then it works.
Open the folder where you have installed PHP, Edit php.ini file
uncomment this line:
extension=php_mysqli.dll
For me this was a missing line in php.ini that solved it, as I copied another php.ini file to my XAMPP installation.
Worth checking if the line: "extension=php_mysqli.dll" exist (if running Windows, but this isn't applicable for OP, as it's a Linux system), or if the "extension_dir" exists and is correct.
1、apt-get install (yum, compile install whatever) php5-mysqlnd extension.
2、if not work, make sure mysqli is loaded
root@x19-ws07-1:/etc/php5/apache2# cat /proc/31682/maps | grep mysql
if is loaded, you can see:
7f2cd3266000-7f2cd3285000 r-xp 00000000 fd:00 864561 /usr/lib/php5/20131226/mysqli.so
7f2cd69ef000-7f2cd6a2e000 r-xp 00000000 fd:00 864559 /usr/lib/php5/20131226/mysqlnd.so
3、if not loaded use php --ini to find config file
xxxx@xxxx:~$ php --ini
Configuration File (php.ini) Path: /etc/php5/apache2
Loaded Configuration File: /etc/php5/apache2/php.ini
Scan for additional .ini files in: /etc/php5/apache2/conf.d
Additional .ini files parsed: /etc/php5/apache2/conf.d/05-opcache.ini,
/etc/php5/apache2/conf.d/20-mysqli.ini
4、if not config extension, config like this and remember restart your web server
xxxx@xxxxx:~$ cat /etc/php5/apache2/conf.d/20-mysqli.ini
; configuration for php MySQL module
; priority=20
extension=mysqli.so
In Linux, you can install MySQL driver extension.
sudo apt-get install php-mysql
In Windows with XAMPP, the driver has already saved in ext directory, but you need to enable it in php.ini. You need to uncomment this line:
extension=php_mysqli.dll
You also need to check the extension directory location in php.ini. I use absolute path (not relative path) declaration to make it works.
extension_dir="your\absolute\path\to\xampp\php\ext"
For example,
extension_dir="C:\xampp\php\ext"
I tried, comment out below line in /etc/php/cli/php.ini file.
extension=php_mysqli.dll
I am using Ubuntu 16.04 on AWS-EC2 instances and PHP 7.0. This solved my problem.
In my case using Windows I had all the necessary extensions uncommented, but it wasn't loading them. Then, I checked the extension directory variable in php.ini and it was as "ext", but then I remembered I'd had a similar problem previously. So what I did was basically put the explicit directory. Something like this:
extension_dir = "C:\php\ext"
Of course the specific ext directory depends entirely on your own setup and locations.
After updating the php.ini file you just have to restart Apache to apply the changes.
If you installed your Apache manually (not using pre-packaged solutions like XAMPP or WAMPP) you just have to use these commands in either a Command Prompt or a Powershell with administrator rights.
net stop Apache2.4
net start Apache2.4
The problem is php's mysql extension might not have installed, if you are using php 7, just issue the below command and install the extension,
sudo apt-get install php-mysql
If your webserver is running with a lower version of MySQL, then you will get this error as MySQLi is not supported in MySQL < 4.1.3
It is highly recommended to go with MySQLi instead of going back to MySQL extension.
I suggest you do the following:
change:
'dbdriver' => 'mysqli',
'dbprefix' => '',
to:
'dbdriver' => 'mysql',
'dbprefix' => '',
in database.php file.
来源：https://stackoverflow.com/questions/33612956/codeigniter-fatal-error-call-to-undefined-function-mysqli-init