Show Hibernate/JPA SQL Statements from Spring Boot

1. Overview

Spring JDBC and JPA provide abstractions over native JDBC APIs, allowing developers to do away with native SQL queries. However, we often need to see those auto-generated SQL queries and the order in which they were executed for debugging purposes.

In this quick tutorial, we’re going to look at different ways of logging these SQL queries in Spring Boot.

2. Logging JPA Queries

2.1. To Standard Output

The simplest way to dump the queries to standard out is to add the following to application.properties:

spring.jpa.show-sql=true

To beautify or pretty-print the SQL, we can add:

spring.jpa.properties.hibernate.format_sql=true

With the above configuration, the log will be printed:

2024-03-26T23:30:42.680-04:00 DEBUG 9477 --- [main] org.hibernate.SQL: 
    select
        c1_0.id,
        c1_0.budget,
        c1_0.end_date,
        c1_0.name,
        c1_0.start_date 
    from
        campaign c1_0 
    where
        c1_0.start_date between ? and ?

While this is extremely simple, it’s not recommended, as it directly unloads everything to standard output without any optimizations of a logging framework.

Moreover, it doesn’t log the parameters of prepared statements.

2.2. Via Loggers

Now let’s see how we can log the SQL statements by configuring loggers in the properties file:

logging.level.org.hibernate.SQL=DEBUG
logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE

The first line logs the SQL queries, and the second statement logs the prepared statement parameters.

The pretty-print property will work in this configuration as well.

By setting these properties, logs will be sent to the configured appender. By default, Spring Boot uses logback with a standard out appender.

If we want to log a query with binding parameters, we can add a property in the application.properties file to do that for us:

logging.level.org.hibernate.orm.jdbc.bind=TRACE

The above property sets the logging level for hibernate to TRACE for JDBC binding, which logs the detailed information along with binding parameters:

org.hibernate.SQL : select c1_0.id,c1_0.budget,c1_0.end_date,c1_0.name,c1_0.start_date from campaign c1_0 where c1_0.start_date between ? and ?
org.hibernate.orm.jdbc.bind : binding parameter [1] as [DATE] - [2024-04-26]
org.hibernate.orm.jdbc.bind : binding parameter [2] as [DATE] - [2024-04-05]

3. Logging JdbcTemplate Queries

To configure statement logging when using JdbcTemplate, we need two additional properties:

logging.level.org.springframework.jdbc.core.JdbcTemplate=DEBUG
logging.level.org.springframework.jdbc.core.StatementCreatorUtils=TRACE

Similar to the JPA logging configuration, the first line is for logging statements and the second is to log the parameters of prepared statements. With the above configurations, SQL logs will be printed with binding parameters:

2024-03-26T23:45:44.505-04:00 DEBUG 18067 --- [main] o.s.jdbc.core.JdbcTemplate: Executing prepared SQL statement [SELECT id FROM CAMPAIGN WHERE name = ?]
2024-03-26T23:45:44.513-04:00 TRACE 18067 --- [main] o.s.jdbc.core.StatementCreatorUtils: Setting SQL statement parameter value: column index 1, parameter value [sdfse1], value class [java.lang.String], SQL type unknown

4. Logging All Kinds of Queries

Using interceptors is the best approach to log all kinds of SQL queries. In this approach, we can intercept JDBC calls, format them, and then log SQL queries in a customized format.

The datasource-proxy library is one of the popular frameworks that intercepts SQL queries and logs them. We need to add its dependency in the pom.xml file:

<dependency>
    <groupId>com.github.gavlyukovskiy</groupId>
    <artifactId>datasource-proxy-spring-boot-starter</artifactId>
    <version>1.12.1</version>
</dependency>

Also, we need to update the property to enable logging for datasource-proxy:

logging.level.net.ttddyy.dsproxy.listener=debug

Now, with this setup, it’ll print a pretty log with details such as query and parameters, among others:

Name:dataSource, Connection:15, Time:1, Success:True
Type:Prepared, Batch:False, QuerySize:1, BatchSize:0
Query:["select c1_0.id,c1_0.budget,c1_0.end_date,c1_0.name,c1_0.start_date from campaign c1_0 where c1_0.start_date between ? and ?"]
Params:[(2024-04-26,2024-04-05)]

One important point to note is that the interceptor approach logs all the queries from JPA, JPQL, and Prepared Statements. Hence, it’s the best approach to log SQL queries with binding parameters.

5. How Does It Work?

The Spring/Hibernate classes, which generate SQL statements and set the parameters, already contain the code for logging them.

However, the level of those log statements is set to DEBUG and TRACE, respectively, which is lower than the default level in Spring Boot — INFO.

By adding these properties, we’re just setting those loggers to the required level.

6. Conclusion

In this short article, we’ve looked at a few ways to log SQL queries in Spring Boot. We also looked into logging binding parameters for the SQL queries. Finally, we discussed why the interceptor approach is the best approach to log SQL queries along with the binding parameters.

If we choose to configure multiple appenders, we can also separate SQL statements and other log statements into different log files to keep things clean.