Ping a MySQL server

Question

Is there a specific method in Java that checks whether a MySQL server is alive?

Shaff

Answer 1

Assuming that you're running in Java 6 or higher, you can use the standard JDBC method Connection.isValid(int timeoutInSecs). Digging into the MySQL Connector/J source, the actual implementation uses com.mysql.jdbc.ConnectionImpl.pingInternal() to send a simple ping packet to the DB and returns true as long as a valid response is returned.

Bascom

Answer 2

The standard MySQL JDBC connector, ConnectorJ, has a lightweight ping. From the docs:

MySQL Connector/J has the ability to execute a lightweight ping against a server, in order to validate the connection. In the case of load-balanced connections, this is performed against all active pooled internal connections that are retained. This is beneficial to Java applications using connection pools, as the pool can use this feature to validate connections.

Basically, ensure that your "ping" query starts with exactly the text /* ping */. Details in the linked docs above. This lets you take advantage of the pinging mechanism rather than doing a (slightly) heavier weight operation.

So basically, doing the query:

/* ping */ SELECT 1

...will trigger the ping mechanism rather than actually doing the "work" of a SELECT 1.

Mind you, if you're talking about checking a MySQL server that you're not currently connected to, just the act of connecting to it verifies that it's there and responding. The above is mostly about checking that an existing connection is still valid.

Footpace

Answer 3

It depends on what method you use to connect to the database. Some drivers, eg MySQL Connector/J do have a ping command:

/**
* Detect if the connection is still good by sending a ping command
* to the server.
* 
* @throws SQLException
*             if the ping fails
*/
public abstract void ping() throws SQLException;

If you an interface that does not support this then a simple method that always works is to connect to the database as you ordinarily would and execute the following query:

SELECT 1

You should get back a result set containing a single row, with a single column, containg the value 1. If this succeeds your MySQL is working.

Scheelite

Answer 4

If you are in command line you can check with using

SELECT 'PONG' AS PING

Creepy