i can't hosting to connect to mysql database on linux i have this error message :
Unable to connect to any of the specified MySQL hosts
i need your help thx; this is my code
I suspect this message came from an exception thrown by your con.Open() call. The message means your attempt to Open() the connection failed because Connector/Net (the .net driver for mySQL) couldn't find the server you asked for. (Never mind the pluralization in "any of the specified MySQL hosts" ; that is for a loadbalancing / failover feature you're probably not using.)
If it took a few seconds for con.Open() to throw the exception, that means there was a timeout. That means the host at x.x.x.x did not respond at all, probably because it's not there or behind a firewall. If you're trying to connect from your home or office to a MySQL server at a hosting service, you may need to go into the hosting service's control panel and whitelist your own machine's IP address.
If Open() threw its exception quickly, it means the host is there, but it is not running a MySQL server.
Pro tip: Always wrap your Open() calls in their own try{}catch(){} clauses; failed database connection attempts are not an unexpected occurrence. Here is an explanation.
Related
I've added the host URL ({hash}.rackspaceclouddb.com), port 3306, and I'm using the same user and password that has access to everything via PhpMyAdmin, but I'm getting a failure when I test the connection. I understand that they run their instances on a private network, which I'm sure is causing the difficulty. Is there some trick I'm not aware of, or is it not possible?
Error message:
Failed: Communications link failure. The driver has not received any packets from the server.
In earlier versions, we've had a similar issue when establishing a connection with MySql. Please update DataGrip to the latest version. Also, make sure to download the latest MySql driver version available in DataGrip.
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.
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).
When in try to start azure storage emulator i get the following error.
Caught exception while probing for SQL endpoint. 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) Number of Sql Errors Reported: 1 Sql Error: System.Data.SqlClient.SqlError: 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
All the Components have been correctly installed .
Kindly Help
Thanx
I managed to fix it by deleting and creating my LocalDb instance. In my case it happened because I installed Azure SDK 2.2 over version 2.1.
The step-by-step to fix it:
Run sqllocaldb i to get your instance name:
C:\Users\myUser>sqllocaldb i
v11.0
Stop LocalDB instance:
C:\Users\myUser>sqllocaldb p v11.0
LocalDB instance "v11.0" stopped.
Delete your LocalDB instance:
C:\Users\myUser>sqllocaldb d v11.0
LocalDB instance "v11.0" deleted.
Create your LocalDB instance with the same name:
C:\Users\myUser>sqllocaldb c v11.0
LocalDB instance "v11.0" created with version 11.0.
Delete database files to allow emulator to recreate db files
C:\Users\myUser\DevelopmentStorageDb22.mdf
C:\Users\myUser\DevelopmentStorageDb22_log.ldf
That should fix your issues.
It looks like your windows account under which you logged in is not sysadmin in sqlexpress instance. Normally emulator uses database within sqlexpress with windows authentication.
The first time you run the Windows Azure storage emulator, an initialization process runs to configure the environment. By default, the initialization process creates a database in SQL Express LocalDB. So, please make sure that your SQLExpress service is running and your login have sufficient rights to use the database within SQLExpress.
If you want to make use of a local instance of an SQL Server to be used by Storage Emulator follow steps listed at http://msdn.microsoft.com/en-us/library/windowsazure/gg433134.aspx.
HTH
Sameer
What i am suspecting is that your LocalDB configuration with emulator is somehow corrupted or misconfigured.
Please follow the blog below to see if you can verify LocalDB instance is ready/working and it is used by Emulator:
http://blogs.msdn.com/b/avkashchauhan/archive/2012/07/10/windows-azure-sdk-1-7-storage-emulator-and-localdb.aspx
If you still have problem the easiest method would be to uninstall SDK 1.7 completely and re-install which will fix any issue with your configuration rather the finding the problem and try to fix which could take longer.
I was getting a similar message:
Probing SQL Instance: 'localhost\SQLExpress'.
Caught exception while probing for SQL endpoint. 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
Number of SqlErrors Reported: 1
SqlError: System.Data.SqlClient.SqlError: 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
No available SQL Instance was found.
One or more initialization actions have failed. Resolve these errors before attempting to run the storage emulator again.
Error: No available SQL Instance was found.
For me the problem was due to the fact that I was not running with administrator privileges.
Might be a little late to the party here, but I've seen this happen if you clear out or remove items in your "C:\Users[USER_NAME]\AppData\Local\Temp" folder.
At the time of writing this, Azurite is the replacement for "azure storage emulator". In my case, I was able to simply follow the steps here https://learn.microsoft.com/en-us/azure/storage/common/storage-use-azurite?tabs=npm#install-azurite to get it installed, and you should be good to go after that.
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.