The "Surviving Connection Closures" page on Confluence still includes autoReconnect=true in the example MySQL configuration

Surviving Connection Closures includes using autoReconnect=true in the connection URL.
This is not recommended to be used, we should just use the validationQuery (which is already included).

The sample URL should look like:

<Resource name="jdbc/JiraDS" auth="Container" type="javax.sql.DataSource"
    driverClassName="com.mysql.jdbc.Driver"
    url="jdbc:mysql://localhost/jiradb?useUnicode=true&amp;characterEncoding=UTF8"
    username="jirauser"
    password="jirapassword"
    maxActive="20"
    validationQuery="select 1" />

Note that I changed the order of properties and added some indenting. This is not necessary, but I think it aids readability.