I am continuously getting below error while connecting to mysql-
Can\'t connect to MySQL server on /ip/address
but mysql is not generating any log for this error. I have below entries in my.cnf file
log=/var/log/mysql_err.log
log-error=/var/log/mysql/mysql_error.log
I am using correct credentials. No issue of conections.
Now how will I determine the exact issue If I'll not get any log ?
Any Idea, how to solve this ?
This is not surprising:
the server can only log an incident it is aware of. However your client does not even reach the server at all! So how should the server know some client has attempted to contact it?
The error message you get clearly indicates that you do have a connection issue.
You can easily make a test to check the most common problems: just open a telnet connection from the system trying to connect to the system the sql server runs on, connect to the mysql port: telnet <ip-of-mysql-server> mysql
On typical unixoid systems "mysql" will be substituted by the "well known port number of mysql, which is 3306. otherwise you have to specify it manually. Do you get a connection at all? I would guess not. This means either the mysql server is not listening where expected (not running or configured otherwise) or the connection is blocked on network level (firewall).
Related
I am using the following DBD::mysql statement to connect to a MySQL database:
use DBI;
# Connect to the database.
my $dbh = DBI->connect("DBI:mysql:database=test;host=localhost",
"usr", "usr's password",
{'RaiseError' => 1});
Is there a way to check if MySQL service is running, before trying to connect to the database? What if the database is running on a remote server?
If you want a solution to check if the service is running without attempting to connect to it, you could use some Perl package to check the process table (works locally only), or check that the MySQL port (3306 by default) has a process listening to it.
I'm not sure what the purpose of this check is, because even if the service is running, the next thing you'll probably want to do is open a DB connection. Opening a DB connection is a quick and easy thing to do, and it has good error reporting if it doesn't work. So your intention to check that the service is running first is just unnecessary overhead.
I would just try to connect as you are doing. This is the most direct way of checking that the service is running, and it works both locally and remotely.
If there's an error, catch the error and interpret the error message. It'll be error 2002 (for localhost) or 2003 (for TCP/IP, whether it's the same host or a remote host).
These errors are mostly reliable. But there could be red herrings, for example if the service is running on a remote host, but your client host can't reach it because of firewalls or routing issues.
If you get an error 1045 (Access Denied), at least you know the service is running and you can reach it, the problem is only that your user & password are incorrect, or you tried to access a schema you don't have privilege to use.
Backstory, I would like to build shiny apps to give to some of our data collectors so they can review what has been collected. We currently house all of our data in a cloud based MySQL server. Ideally, I would like the shiny app to pull data directly from the MySQL server so it can be fully automated without any data pulls and up 24/7.
I have been trying to first just build the connection between R and MySQL using the RMySQL package and can't seem to get it working. I have set up a specific username/password for this connection that is read only(however I have also tried my regular username which has all privileges granted). This is the code I am running;
mydb=dbConnect(
MySQL(),
user='myuser',
password='mypass',
dbname='vgtg',
host='ipaddress',
port=3306,
)
Obviously the 'ipaddress' of the server has been changed for the sake of posting here but it is a generic looking address like
'192.168.1.1'
When I run the code above I get this error message;
Error in .local(drv, ...) :
Failed to connect to database: Error: Can't connect to MySQL server on
'ipaddress' (0)
I have tried looking for previous questions posted but none seem to be exactly this error message that I am receiving. It makes me think that for some reason RMySQL is looking locally for the server when it is actually a cloud based, remote, server.
Also, is there anything more I should set up server side to allow the connection? I do have a server admin to help out but I am not sure how familiar he is with R and likewise I am not particularly familiar with working with servers. He has opened port 3306 for me and is able to see my attempts to connect through the port.
Your syntax is correct with the exception of
port=3306,
You need to drop the comma. That said, the error you received is unrelated to the syntax.
Without knowing the details of your setup, it is hard to diagnose. Where does the MySQL DB reside? For example, if it is on an AWS RDS instance, then the host isn't a standard IP address, it is something like this
mydb.cm1abc2v4mod.us-west-1.rds.amazonaws.com
Assuming that the IP address you used is correct, then the problem is most likely on the server. You need to ensure that port 3306 is open to traffic. Otherwise, R will not be able to connect to the DB.
First of all I apologize for my English is not perfect.
I'm trying to connect to mysql database remotely.
I have already done the basic steps such as, for example, comment the bind address in my.cnf.
I gave permissions to the appropriate users in MySQL.
I tried with my friend to do it connect to the database, and it worked but we were in the same room with the same router.
Now I'm home and I tried to connect my friend, but I always get error:
ERROR 2003 (HY000): Can not connect to MySQL server ....
Maybe it's a problem of my home router? I can not even do the telnet.
P.S. I've also taken steps to set the firewall.
Some reasons for that,
mysqld is not running on the local host. Check your operating
system's process list to ensure the mysqld process is present.
You're running a MySQL server on Windows with many TCP/IP connections
to it. If you're experiencing that quite often your clients get that
error, you can find a workaround here: Section B.5.2.2.1, “Connection
to MySQL Server Failing on Windows”.
Check whether the server is running on that host by executing telnet
some_host 3306 and pressing the Enter key a couple of times. (3306 is
the default MySQL port number. Change the value if your server is
listening to a different port.) If there is a MySQL server running
and listening to the port, you should get a response that includes
the server's version number. If you get an error such as telnet:
Unable to connect to remote host: Connection refused, then there is
no server running on the given port.
Look at this mySQL full documentation, it will be helpful.
I'm running a local copy of WordPress on XAMPP/WinXP for development, but would like to maintain a connection to the remote database. I keep getting "Error establishing database connection" no matter what I try.
On the same PC, I can connect to the remote mySQL DB using any number of mySQL clients, and on the mySQL side, the both the user and the database are set to accept incoming requests from any wildcard domain. I can also easily ping the remote database server from my PC (though I don't know how to do it from WITHIN XAMPP).
Is XAMPP its own little universe that can't reach through to the outside world? Or is there something I'm clearly overlooking that's not letting me connect?
Errors
Warning: mysql_connect() [function.mysql-connect]: Premature end of data (mysqlnd_wireprotocol.c:553) in C:\xampp\htdocs\dbtest.php on line 5
Warning: mysql_connect() [function.mysql-connect]: OK packet 1 bytes shorter than expected in C:\xampp\htdocs\dbtest.php on line 5
Warning: mysql_connect() [function.mysql-connect]: mysqlnd cannot connect to MySQL 4.1+ using the old insecure authentication
Edit
Thanks to #Michael for suggesting I just create a simple connection script so I can get better insight into the actual error that's being thrown. This revealed that it had to do with the old_password setting in mySQL. See my Answer below for a full description of how to resolve this issue.
Here's the test script I put inside my xampp\htdocs folder and tested out:
<?php
$mysqli = new mysqli('my.server.address', 'user_name', 'password', 'database_name');
if ($mysqli->connect_error){
die ("Connect error: " . $mysqli->connect_error );
}
I'm not really clear on why this became an issue on my XAMPP installation, since I'm also running PHP 5.3.x on the server's local box and wasn't experiencing those issues there. However, it has to do with my mySQL server running in "old password" encryption mode. Newer versions of PHP won't allow those kinds of connections, so you need to update your mySQL server to use the newer password encryption. Here are the steps, assuming you have control over the mySQL server. If you don't, that falls out of the scope of my knowledge.
locate the configuration file for the mysql server called my.cnf. I found mine at /etc/my.cnf. You can edit it with sudo nano /etc/my.cnf
Look for a line that says old_passwords=1 and change that to old_passwords=0. You have now told the server that the next time it is run, and it is asked to encrypt a password using the PASSWORD() command, it use the new 41-character encryption rather than the 16-character 'old' style encryption
Now you have to restart your mysql server / service. YMMV, but on Fedora that was easily done with sudo service mysqld restart. Check your OS' instructions for restarting the mysql daemon or service
Now we have to actually edit our user table within mysql. So open up an interactive shell to mysql (on the server you can type mysql -uYourRootUsername -pYourRootPassword)
Change to the mysql database. This is the database that holds all the good stuff for server operation and authentication. You must have root access to work with this database. If you get an 'access denied' you're SOL. Sorry. use mysql; will switch to that database
Now we want to update the user that was giving you grief. Ultimately you'll probably want to update all your users, but for now, we're just focusing on the user that threw the error. update user set Password=password('YOUR_PASSWORD') where User='YOUR_USERNAME';
Now you just need to tell mysql to use the new password for authentication when that user attempts to connect. flush privileges;.
You should be good to go!
I am trying to connect remotely to SQL Server 2008 R2 Express on a server running Windows Server 2008 R2. I receive the following error:
A network-related or instance-specific error occurred while
establishing a connection to SQL Server. The server was not found or
was not accessible. Verify that the instance name is correct and that
SQL Server is configured to allow remote connections. (provider: TCP
Provider, error: 0 - A connection attempt failed because the connected
party did not properly respond after a period of time, or established
connection failed because connected host has failed to respond.)
I think the problem might be related to my connection string, because I am not sure exactly what it should be. I understand the connection string should take the form:
Data Source=123.123.123.123\InstanceName;Initial Catalog=MyDBName;user id=MyUserName;password=MyPassword;
The instance name of my SQL Server installation takes the form ComputerName\SQLEXPRESS. This is what I see when I log in to Management Studio on the server. So should the connection string begin with
Data Source=123.123.123.123\ComputerName\SQLEXPRESS
This looks wrong because of all the slashes. I have tried to omit the computer name thus:
Data Source=123.123.123.123\SQLEXPRESS
I also read somewhere that you can specify a port so I have also tried
Data Source=123.123.123.123,1433\SQLEXPRESS
because I understand that 1433 is the TCP port used by SQL Server and
Data Source=123.123.123.123,1434\SQLEXPRESS
because I understand that 1434 is the UDP port used by SQL Server browser.
I have also tried every combination of these and they all give the same error.
These are the steps I have taken to enable remote browsing on the server:
In Management Studio, right click the instance, go to Properties, Security and check SQL Server and Windows Authentication Mode. On the connections tab I have checked "Allow remote connections to this computer".
In SQL Server Configuration Manager I have enabled all four connection options (Shared Memory, Named Pipes, TCPIP and Via) under every node they occur. Under protocols for SQL Express I have tried specifying port 1433 and also leaving it blank with TCP Dynamic Ports set to 0 (which I think is meant to enable dynamic ports).
I have created firewall exceptions for TCP Port 1433, UDP Port 1434, and program exceptions for sqlservr.exe and sqlbrowser.exe.
If someone could tell me which of the four versions of the DataSource part of the connection string I should be using it would be a great help, even if it did not solve the problem. It would mean that everything I try subsequently I would only have to test once instead of four times.
Thanks in advance for any help!
Where did you enter the firewall exceptions, on your machine, on the server, or both?
The second connection string is the only really valid one. Can you telnet to the server on port 1433? Can you connect to the instance from Management Studio remotely and the problem is only from your code where the connection string is? Did you try running the same code on the server? Did you try forcing TCP/IP (vs. named pipes/shared memory etc) adding the following parameter to your connection string:
Network=DBMSSOCN;
This question comes up quite a lot and I'm sure you're hitting something that others have hit before. Have you gone through this article, "How to troubleshoot connecting to the SQL Server Database Engine"? Also there are 20+ questions on here that mention this error message and Express, according to this search result. I suggest double-checking your settings against some of the items in those answers that solved the issue for other users.