与在代码中手动创建数据源相比，为什么在Jboss EAP 6.4中的standalone.xml中创建数据源具有更长的响应时间

Question

I have a web application where i am using jboss EAP 6.4. There i am using two configurations for creating datasource. Datasource is defined in standalone file also and if while creating datasource object any exception is thrown then data source is created manually in code. Code for the same is given below:

@Bean
    public DataSource getDataSource() {
        try {
            Object object = new JndiTemplate().lookup(JNDI);
            return DataSource) object;
        } catch (NamingException e) {
            DriverManagerDataSource dataSource = new DriverManagerDataSource();
            dataSource.setDriverClassName(---);
            dataSource.setUrl(---);
            dataSource.setUsername(---);
            dataSource.setPassword(---);

            return dataSource;
        }
    }

Here is my standalone.xml snippet

<datasource jta="false" jndi-name="xyz" pool-name="xyDatasource" enabled="true" use-ccm="false">
                    <connection-url>jdbc:oracle:thin:@localhost:1521:xe</connection-url>
                    <driver>OracleJDBCDriver</driver>
                    <pool>
                        <min-pool-size>20</min-pool-size>
                        <max-pool-size>30</max-pool-size>
                        <use-strict-min>true</use-strict-min>
                        <flush-strategy>FailingConnectionOnly</flush-strategy>
                    </pool>
                    <security>
                        <user-name>abc</user-name>
                        <password>xyz</password>
                    </security>
                    <validation>
                        <validate-on-match>false</validate-on-match>
                        <background-validation>false</background-validation>
                    </validation>
                    <statement>
                        <share-prepared-statements>false</share-prepared-statements>
                    </statement>
       </datasource>

The problem here is when connection is created successfully using standalone version datasource at that time the response time for all the requests are pretty high as compared to when its is created in code in catch condition.

I searched a lot but didn't find any reason for it.

Answer 1

As per my understanding, when code is getting connection via datasource defined in standlone.xml file, it gets connection from pool defined in configuration. It doesn't have to take direct connection from database every time while performing operations.

However when connecting to database directly using code, its code's responsibility to get connection from database and then do lookup.

Refer https://docs.oracle.com/javase/tutorial/jdbc/basics/sqldatasources.html