Logging SQL statements in Grails 3

You can enable logging of the SQL queries that Hibernate executes via the logSql property of your datasource config in either application.yml or application.groovy. Setting logSql to true enables logging to stdout. You will see output similar to the one below:

Hibernate: create table book\_chapter\_page\_count (book\_id bigint not null, chapter\_page\_count\_integer integer) ENGINE=InnoDB

Hibernate: alter table book\_chapter\_page\_count add constraint FK87brho4gbq6gbns18fnschhsx foreign key (book\_id) references book (id)

The logged SQL can be formatted by setting formatSql to true.

Hibernate: 
    
    create table book\_chapter\_page\_count (
        book\_id bigint not null,
        chapter\_page\_count\_integer integer
    ) ENGINE=InnoDB
Hibernate: 
    
    alter table book\_chapter\_page\_count 
        add constraint FK87brho4gbq6gbns18fnschhsx 
        foreign key (book\_id) 
        references book (id)

Turning on SQL logging can be an effective way to a look at what is happening behind the scenes when your encounter issues with GORM. I have come across scenarios were it fails silently without any feedback.

As always you can head over to github for an example project on this.