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Unable To Connect To Any Of The Specified MySQL Hosts?
Unable To Connect To Any Of The Specified MySQL Hosts? If you get this error, the MySQL service may not be running on the server. To check this, open the Windows “Services” program and see if the MySQL service is there. If it is, make sure incoming connections to port 3306 are allowed. You can also try disabling any antivirus programs that are running on the server.
MySQL is an open-source database program that runs on a variety of operating systems. It is used by many applications, including websites and mobile apps. It is available for free, although it has an “enterprise edition” version that can be licensed.
Each server in a MySQL Cluster is called a node. A node can be either a management or a data node. The management node (MGM) manages the configuration information of the cluster, and it also hosts the cluster log file. Data nodes store the data, and they transparently handle replication, failover, and load balancing.
The SQL node is a MySQL server (mysqld process) that connects to the data nodes and provides SQL functionality. Each SQL node is responsible for one partition of the cluster’s data. The NDBCLUSTER storage engine automatically shards tables across data nodes for performance and availability reasons. This means that any change to a table in one SQL node is immediately visible on all the other SQL nodes.
Application nodes use standard MySQL clients (mysqld, NDBCLUSTER API, and the MySQL C, Perl, Java, Python, and Ruby APIs) to access the cluster. These clients must be able to communicate with both the MGM node and the SQL node, and they must be able to fetch records in properly sized batches. This is achieved by setting a query option that determines how large a batch should be, in terms of the number of rows and bytes.
Many organizations use firewalls to help protect their networks. Firewalls can be configured at the network or host level. Network firewalls are ideal for a broader scope of protection, while host-based firewalls are better suited for individual machines.
Sometimes the problem is caused by the Windows firewall or any other firewall that is part of an antivirus program, you need to make sure that incoming connections are allowed. To do this you need to open a command prompt and type “netsh win firewall set port 3306 allow”.
Another possible issue is that the MySQL service is not running. To resolve this you will need to check if the service is running on your server, if not, then start it. To do this you can open a command prompt and type “start MySQL”. Make sure that the database user is not restricted and that the password for the MySQL server user is correct. You can test this by pinging the server from a computer that is not in your network. If you get a reply then the password is correct and the firewall is not blocking the connection.
If you are able to connect to your MySQL server from other workstations but not from the server itself, it may be a problem with the firewall. Check the Windows Firewall settings and make sure incoming traffic is allowed on port 3306. If you are using a proxy or VPN to connect to the server, it is possible that it’s not working. Try changing the proxy settings or reconnecting to the VPN server.
Another possibility is that your database files are set to Read Only. You can change this in C:mysqldata by right-clicking and selecting Properties. If the Choose Database window still displays, Unable To Connect To Any Of The Specified MySQL Hosts, you can temporarily disable any backup or antivirus programs that are running and attempt to connect. If you continue to have trouble, it is likely that the installation was not completed correctly. See the MySQL installation guide for more information and contact support. This error can also occur if the MySQL service is not running. To resolve this, go to the Services menu and start it.
The error message Unable To Connect To Any Of The Specified MySQL Hosts indicates that the MySQL binary has not been able to bind itself to port 3306 (or one of its variants). This may be due to a firewall on the server or on a workstation. Check the Windows firewall to ensure incoming traffic on port 3306 is allowed or that an antivirus program is not interfering. Also, ping your server from a different workstation to see if you can reach it.
This is a common problem when using a home server to host your business website. Generally, it is caused by an antivirus program or a backup software preventing the MySQL binary from being able to connect to MySQL. You can try to temporarily disable these programs to resolve the issue.
For a more permanent solution, the best option is to install mysql cluster packages. These are available from various distributions or can be built from source. The only executable required on each data node host is ndbd, which by default is placed in the /usr/local/mysql directory when doing a source build. The rest of the configuration files can be shared between machines.
If you are still having trouble, try to increase the connection timeout on the MySQL server to 60 seconds or higher. This should allow your application to connect to the database and resolve the error message.