<datasources>
                <datasource jndi-name="java:jboss/DefaultDS" pool-name="MySQLDefaultDS" enabled="true" jta="true" use-java-context="true">
                    <connection-url>jdbc:mysql://localhost:3306/myappdbname</connection-url>
                    <driver>mysql</driver>
                        <transaction-isolation>TRANSACTION_READ_COMMITTED</transaction-isolation>
                    <pool>
                        <min-pool-size>10</min-pool-size>
                        <max-pool-size>40</max-pool-size>
                    </pool>
                    <security>
                        <user-name>root</user-name>
                        <password>xxx</password>
                    </security>
                    <validation>
                        <valid-connection-checker class-name="org.jboss.jca.adapters.jdbc.extensions.mysql.MySQLValidConnectionChecker"/>
                        <validate-on-match>
                            false
                        </validate-on-match>
                        <background-validation>
                            false
                        </background-validation>
                        <use-fast-fail>
                            false
                        </use-fast-fail>
                    </validation>
                    <timeout>
                        <blocking-timeout-millis>
                            5000
                        </blocking-timeout-millis>
                    </timeout>
                </datasource>
                <drivers>
                    <driver name="mysql" module="com.mysql.jdbc"/>
                </drivers>