我项目的设置是 -
- 使用 Spring JDBC 进行持久化
- 使用 Apache DBCP 1.4 进行连接池管理
- 在 Linux 上使用 Mysql 5 数据库
这是我的应用程序日志,记录了与数据库的交互。
2013-01-29 15:52:21,549 DEBUG http-bio-8080-exec-3 org.springframework.jdbc.core.JdbcTemplate - Executing SQL query [SELECT id from emp]
2013-01-29 15:52:21,558 DEBUG http-bio-8080-exec-3 org.springframework.jdbc.datasource.DataSourceUtils - Fetching JDBC Connection from DataSource
2013-01-29 15:52:31,878 INFO http-bio-8080-exec-3 jdbc.connection - 1. Connection opened org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
2013-01-29 15:52:31,878 DEBUG http-bio-8080-exec-3 jdbc.connection - open connections: 1 (1)
2013-01-29 15:52:31,895 INFO http-bio-8080-exec-3 jdbc.connection - 1. Connection closed org.apache.commons.dbcp.DelegatingConnection.close(DelegatingConnection.java:247)
2013-01-29 15:52:31,895 DEBUG http-bio-8080-exec-3 jdbc.connection - open connections: none
2013-01-29 15:52:41,950 INFO http-bio-8080-exec-3 jdbc.connection - 2. Connection opened org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
2013-01-29 15:52:41,950 DEBUG http-bio-8080-exec-3 jdbc.connection - open connections: 2 (1)
2013-01-29 15:52:52,001 INFO http-bio-8080-exec-3 jdbc.connection - 3. Connection opened org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
2013-01-29 15:52:52,002 DEBUG http-bio-8080-exec-3 jdbc.connection - open connections: 2 3 (2)
2013-01-29 15:53:02,058 INFO http-bio-8080-exec-3 jdbc.connection - 4. Connection opened org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
2013-01-29 15:53:02,058 DEBUG http-bio-8080-exec-3 jdbc.connection - open connections: 2 3 4 (3)
2013-01-29 15:53:03,403 DEBUG http-bio-8080-exec-3 org.springframework.jdbc.core.BeanPropertyRowMapper - Mapping column 'id' to property 'id' of type int
2013-01-29 15:53:04,494 DEBUG http-bio-8080-exec-3 org.springframework.jdbc.datasource.DataSourceUtils - Returning JDBC Connection to DataSource
从日志中可以清楚地看到两件事情:
- 当收到第一个查询请求时,连接池才开始创建连接。
- 一个包含4个连接的连接池需要近30秒的时间来初始化。
- 如何配置DBCP以在启动时自动初始化?
- 创建连接真的需要那么长时间吗?
dbcontext的内容为:
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="${db.driver}" />
<property name="url" value="${db.jdbc.url}" />
<property name="username" value="${db.user}" />
<property name="password" value="${db.password}" />
<property name="maxActive" value="20" />
<property name="initialSize" value="4" />
<property name="testOnBorrow" value="true" />
<property name="validationQuery" value="SELECT 1" />
</bean>