{"id":26263,"date":"2014-06-09T07:00:58","date_gmt":"2014-06-09T04:00:58","guid":{"rendered":"http:\/\/www.javacodegeeks.com\/?p=26263"},"modified":"2014-06-06T13:48:49","modified_gmt":"2014-06-06T10:48:49","slug":"springhibernate-improved-sql-logging-with-log4jdbc","status":"publish","type":"post","link":"https:\/\/www.javacodegeeks.com\/2014\/06\/springhibernate-improved-sql-logging-with-log4jdbc.html","title":{"rendered":"Spring\/Hibernate improved SQL logging with log4jdbc"},"content":{"rendered":"

Hibernate provides SQL logging out of the box, but such logging only shows prepared statements, and not the actual SQL queries sent to the database.<\/p>\n

It also does not log the execution time of each query, which is useful for performance troubleshooting. This blog post will go over how to setup Hibernate query logging, and then compare it to the logging that can be obtained with log4jdbc<\/a>.<\/p>\n

The Hibernate query logging functionality<\/h3>\n

Hibernate does not log the real SQL queries sent to the database. This is because Hibernate interacts with the database via the JDBC driver, to which it sends prepared statements but not the actual queries.<\/p>\n

So Hibernate can only log the prepared statements and the values of their binding parameters, but not the actual SQL queries themselves.<\/p>\n

This is how a query looks like when logged by Hibernate:<\/p>\n

select \/* load your.package.Employee *\/ this_.code, ... \r\nfrom employee this_ \r\nwhere this_.employee_id=?\r\n\r\nTRACE 12-04-2014@16:06:02  BasicBinder - binding parameter [1] as [NUMBER] - 1000<\/pre>\n
See this post Why and where is Hibernate doing this SQL query?<\/a> for how to setup this type of logging.<\/p>\n
Using log4jdbc<\/h2>\n
For a developer it’s useful to be able to copy paste a query from the log and be able to execute the query directly in an SQL client, but the variable placeholders ?<\/code> make that unfeasible.<\/p>\n
Log4jdbc in an open source tool that allows to do just that, and more. Log4jdbc is a spy driver that will wrap itself around the real JDBC driver, logging queries as they go through it.<\/p>\n
The version linked from this post provides Spring integration, unlike several other log4jdbc forks.
 
<\/div> <\/div><\/p>\n
Setting up log4jdbc<\/h3>\n
First include the log4jdbc-remix library in your pom.xml. This library is a fork of the original log4jdbc:<\/p>\n
<dependency>\r\n    <groupId>org.lazyluke<\/groupId>\r\n    <artifactId>log4jdbc-remix<\/artifactId\r\n    <version>0.2.7<\/version>\r\n<\/dependency><\/pre>\n
Next, find in the Spring configuration the definition of the data source. As an example, when using the JNDI lookup element this is how the data source looks like:<\/p>\n
<jee:jndi-lookup id=\"dataSource\" \r\n    jndi-name=\"java:comp\/env\/jdbc\/some-db\" \/><\/pre>\n
After finding the data source definition, rename it to the following name:<\/p>\n
<jee:jndi-lookup id=\"dataSourceSpied\" \r\n    jndi-name=\"java:comp\/env\/jdbc\/some-db\" \/><\/pre>\n
Then define a new log4jdbc data source that wraps the real data source, and give it the original name:<\/p>\n
<bean id=\"dataSource\" class=\"net.sf.log4jdbc.Log4jdbcProxyDataSource\" >         \r\n     <constructor-arg ref=\"dataSourceSpied\" \/>         \r\n     <property name=\"logFormatter\">                    \r\n         <bean class=\"net.sf.log4jdbc.tools.Log4JdbcCustomFormatter\" >\r\n             <property name=\"loggingType\" value=\"SINGLE_LINE\" \/>\r\n             <property name=\"margin\" value=\"19\" \/>   \r\n             <property name=\"sqlPrefix\" value=\"SQL:::\" \/>            \r\n         <\/bean>            \r\n     <\/property>     \r\n<\/bean ><\/pre>\n
With this configuration, the query logging should already be working. It’s possible to customize the logging level of the several log4jdbc loggers available.<\/p>\n
The original log4jdbc<\/a> documentation provides more information on the available loggers:<\/p>\n