PHP mysql_connect cannot resolve Host name when sessions are enabled - php

Crazy right? Sample code:
<?php
session_start();
$hostname="samplehost";
$username="sampleuser";
$password="samplepass";
$dbname="sampledb";
$link = mysql_connect($hostname, $username, $password) or die(mysql_error());
mysql_select_db($dbname, $link);
?>
Will throw Unknown MySQL server host 'samplehost' (2). If we remove the session_start() or just do a session_destroy() before the mysql_connect(), it works correctly. Basically, if we have a session open, its like mysql_connect wont resolve the host name. The host name we use for the server is correctly added to /etc/hosts.
It's a production server running PHP 5.3.2-1ubuntu4.7 - just started happening today. Anyone run into this?
edit: should mention, with or without sessions, we can specify the IP of the DB server, and it works correctly.

If someone comes across this - it turns out to be a an issue with the amount of Virtual Hosts we had in Apache. Appears when you start hitting the limit on file descriptors, you get some odd symptoms - it was finally diagnosed when we started getting a 'Too many open files' error in PHP.
It was a legacy setup in how we were automatically generating vhosts for new domains. Better managed that process, reduce the amount of vhosts and the issues went away.

Why don't you just connect first, then start the session?

Related

WampServer, mysqli_connect (HY000/1045) Access denied for user

I'm using wampserver 3.2.0 and mysql 8.0.18.
I already reinstalled the wampserver and started everything from the begining after many tries, so now with fresh reinstall and clear datas this is what i did:
Set password for the root "pass123", after this i created a database (testdb) at wampserver>mysql>mysql console (i was logged in as root), then filled it up with the data i needed. Checked the user accounts/privileges, and the database privileges, i have all the privileges everywhere as root, but still i get this error message: screenshot about the problem
my code:
<?php
$ser="localhost";
$user="root";
$pass="pass123";
$db="testdb";
$connect = mysqli_connect($ser ,$user ,$pass ,$db) or die("Connection Failed");
echo "Connected!"
?>
Thanks in advance! (i'm new to php)
I solved the problem by specifying the exact port number used by mySQL.
The standard port is 3308, so just change the following line:
$ser="localhost:3308";
Not the actual SOLUTION, but, it works fine. Easy.
If you have the same problem, DO NOT use WAMP, use XAMPP instead.
With the same settings, it works.

phpGrid "Error: Could not connect to the database" debugging

I have implemented a phpGrid that works in my dev environment but just keeps saying:
Error: Could not connect to the database
in production
I am logging failed attempts at MySQL connections in the logs on and if I put in a dodgy username and password in the conf.php files username/password it does not show up in the log (I've tested the log is working by attempting to connect with bad credentials via a terminal.
The host is just "localhost" I am using PDO connections elsewhere within my code and the are all connecting using "localhost" so I see now reason why this would be a problem.
In the conf.php I've turned on:
define('DEBUG', true);
And on my grid I have:
$dg -> enable_debug(true);
But I just keep getting this stupid error that tells me nothing about what's really going on...
It happened to me as well. Finally I was able to figure out. The reason is mySQLi was not enabled on the server. I enabled it and it works now.
Sorry, i cannot add a commant and sorry for my english.
If you are using PHP 5.5 try:
error_reporting=E_ALL^E_DEPRECATED
at top of the page for the time being.
For the files on your production machine: proof if they are still in utf-8 encoding

Strange behavior of mysql_connect in PHP

This is how a connection is created to MySQL server at localhost
$Connection = mysql_connect("localhost","root","");
But MySQL seems ignoring my username and password, even if I create the connection with some nonsense username & password:
$Connection = mysql_connect("localhost","nonsense-username","");
Both cases give me the $Connection as "resource(39) of type (mysql link)". And this only happens when password is blank. Is it a default behaviour of MySQL to accept any username when password is blank?
But it is supposed to have $Connection equal 'false' when such 'nonsense-username' given. Anything wrong?
I'm going to assume that you've setup the MySQL server on your own computer, without configuring users, permissions or things like that. If that's the case, then the cause might be SQL Safe Mode. If in your php.ini file, sql.safe_mode is set to 1, then PHP will substitute any arguments you pass to mysql_connect() with their defaults. That would certainly explain this behavior. Try looking at phpinfo() to see if that's the case.
It seems you have not restarted the webserver after install of php-mysql. Please restart the webserver it should work.
I spent two hours debugging that and the simple solution was restart

PHP SQL Server Connection

I am using SQL Server as my backend for program.when i am try to connect with database which not shows any type of errors,but it is not working.Which is not getting connection.
My code is like
mssql_connect('servername', 'db_user', 'db_password') or die('Error');
The funny thing is which is not connecting and also which is not show message Error.
How can we enable SQL Server configuration using php program (what is the script for that.not manually). How could we know the actual status of SQL Server in server?
My application is working properly in local;the problem is about public hosting.
turn on error_reporting in your php.ini. it might be some other section of code that is causing the issue, since you say that it doesn't go to die part. try checking first if it even goes to the mysql_connect() part. if possible post a part of your code around the mysql_connect.
I would bet it is localhost, I have, nor do I ever wish to, see the database sitting on the same server as the website. Check in your hosting control panel for the proper connection string.

Confusing PDO-only problem : Can't connect through socket/Access denied/Can't connect to server (shared host)

So the problem changed from what it was, i'll leave the original question below to prevent bad reviews on answers like I had after someone editing his question I answered :
So I am working on a (really lame) shared hosting which has PDO installed, but it doesn't work.
With default parameters
<?php
try {
$dbh = new PDO('mysql:host=localhost;dbname=THE_DB_NAME', 'THE_USER', 'THE_PASSWORD');
echo 'Connected to database';
}
catch(PDOException $e)
{
echo $e->getMessage();
}
?>
it throws this message :
SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
With a simple mysql_connect, it works.
And the socket path seems correct (both phpinfo and this query :
show variables like 'socket';
confirm.
Localhost redirects to 10.103.0.14 (this data comes from mysql_get_host_info() and in phpMyAdmin)
In the PDO, if i replace localhost by 127.0.0.1 i will get
SQLSTATE[HY000] [2003] Can't connect to MySQL server on '127.0.0.1' (111)
And if i replace localhost by 10.103.0.14 :
Access denied for user 'USER_NAME'#'10.103.0.14' (using password: YES
Both IP adress (127.0.0.1 and 10.103.0.14) work with mysql_connect.
So apparently the problem comes from the PDO connection.
Does somebody knows where this could come from, or/and any way to fix it ?
Some server datas :
The PHP Version : 5.2.10
You can see the server's phpinfo : http://web.lerelaisinternet.com/abcd.php?v=5
No command line possible.
(i know it should be the tech suport's job, but they're reaaaaaly slow)
Thanks
Previous question :
How to find the mysql.sock on a shared host (tricky way needed...)
So today's problem is : The PDO connection doesn't work on a shared host, and it's supposed to (it's installed on the server).
Just a basic PDO connection :
<?php
try {
$dbh = new PDO('mysql:host=localhost;dbname=THE_DB_NAME', 'THE_USER', 'THE_PASSWORD');
echo 'Connected to database';
}
catch(PDOException $e)
{
echo $e->getMessage();
}
?>
throws this message :
SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
A regular mysql connection :
mysql_connect("localhost", "THE_USER", "THE_PWD") or die(mysql_error());
mysql_select_db("24DLJLRR1") or die(mysql_error());;
echo 'Connected to database <br/>';
works fine.
So apparently it cannot find the .sock.
I think specifying the correct address should work, i tried some "classic" mysql path that I found on internet, without success.
The phpinfo says it is at this adress (/var/lib/mysql/mysql.sock)
(The PHP Version is 5.2.10)
You can see the server's phpinfo : http://web.lerelaisinternet.com/abcd.php?v=5
So i am trying to figure out where the hell it is !!!
I tried to look in the phpMyAdmin interface, but i couldn't find the info, plus it seems that phpMyAdmin connects to a different server (it has a different IP adress, and trying to connect to it with php gives a "Wrong password" error). The mysql_connect also connects to this adress, i think it redirects to a different server with some internal password/login.
Well if you have any idea of how to obtain this info (the provider's technical support is "fixing the problem"... it's been 1 month...).
Also maybe the problem comes from somewhere else, but the same stuff works on other shared hosts...
The need of PDO is because I use the Symfony framework with Doctrine for this website, and the Doctrine plugin needs PDO... I don't want to redo the website from scratch !
Thanks for your help !
This was already marked as answered, but not really solved (without changing databases).
So, just in case someone like me also experiences this problem...
The easiest way to fix this is to first get the socket path (either by looking in the php.ini file or by using: phpmyadmin or the console (or construct it in mysql or mysqli)
...to run the following query (anything but PDO):
show variables like 'socket'; //as mentioned by symcbean
THEN, in the PDO connection string, change it to use the socket instead of a hostname:
$dbc = new
PDO("mysql:unix_socket=/var/run/mysqld/mysqld.sock;dbname=$DBName",
$User, $Password, array(PDO::ATTR_PERSISTENT => true)); // using
persistent connections
This worked for me.
FWIW, I had this issue and changed my host from 'localhost' to '127.0.0.1'.
I have no clue why localhost wasn't working, but that did the trick.
Odd thing is, we have tons of servers and it works on almost every one using 'localhost'
Is your server running with SeLinux enabled (enforcing)? If it is, try running as root:
# setsebool -P httpd_can_network_connect on
Can you try 127.0.0.1 as the server name instead of localhost?
IIRC, with some mySQL drivers / adapters, this decides whether the socket is used for establishing the connection or not.
Using the connection which works, run the query:
show variables like 'socket';
(this behaves just like a select statement)...and you'll get the path of the running socket.
Then check the file permissions.
I had the problem that production version worked just fine and a test version wasn't able to connect PDO :/
both versions was located at same servers, test in a sub directory.
The fix was replacing in DSN the localhost for ip.
'mysql:host=localhost;dbname=db'
became
'mysql:host=127.0.0.1;dbname=db'
try:
exec('`which mysql_config` --socket');
this should show you the configured socket.
I found the reason for the strange behaviour. If bind-address is different to 127.0.0.1 or 0.0.0.0 (all addresses) PDO can't connect to 127.0.0.1.
For what it's worth, I found this page after having the exact same issue. I am on a server running Apache & PHP only - MySQL is installed on another machine. I tried both the DNS name of the server and its IP and confirmed I could ping it. A PHP app on the same machine is talking to the database fine, using old syntax mysql_connect( ). But PDO from the CLI was throwing this error.
The solution for me was to check my DSN. Any typo in the DSN itself is ignored silently, and PDO assumes you mean localhost. My issue was I had "name=" instead of "dbname=" in the DSN.
The Issue In the Mysql configuration It you need to disable the option of skip-networking
in my.conf configuration file this should work fine
reference
http://www.wolfcms.org/forum/post7098.html#p7098
I just solved a similar issue. My guess is you probably replaced your mysql_connect() statement with the PDO equivalent. Don't forget you still have lots of other code dependent on that old connection statement. Try keeping the mysql_connect in place while writing in the PDO code.
What worked for me was specifying the port number like so:
mysql:hostname;port=3306;dbname=dbname;
This got it to work when connecting to a local database. Now I'm working on getting it to work with a remote db.
My problem may be different to the OP, but I thought it was worth posting. I did a software upgrade on a VM, then rebooted and got the OP's error message. It turned out to be an out-of-memory problem preventing mysql from starting. Deleting a few large files made the problem go away.
One year later, I found a solution for this issue : using a SQLite database. PDO worked fine, but not with MySQL
** EDIT ** as everyone is downvoting this: This solved my issue (I'm the OP). I was using Doctrine, so switching RDBMS was easy and quick. Also the website was some a home made CMS, with very few trafic, so SQLite was fine.
I know it's not a real "Answer" to the problem, but if someone is in the same context: a crappy shared hosting which you can't change with this weird PDO-MySQL bug AND is using doctrine. This IS a solution. I can delete this answer, but if I had thought of this at the time of the OP, I would have saved a lot of time.

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