logback additivity is false still hibernate sql logs generated on Tomcat console - sql

Question

How to generate 2 log files; One will log Hibernate sql messages generated by show-sql = true property. And another will log rest of the Hibernate logs.
I have configured logback.xml as shown below:
<logger name="org.hibernate" level="debug" additivity="false">
<appender-ref ref="hibernate" />
</logger>
<logger name="org.hibernate.SQL" additivity="false">
<appender-ref ref="hibernate-sql" />
</logger>
It is generating 2 log files as expected. However, It is duplicating hibernate-sql log messages in Tomcat console, hibernate appender, and hibernate-sql appender.
How could I restrict logback to generate Hibernate sql logs in hibernate-sql appender only?

Answer 1

Hibernate writes the generated SQL in two distinct and completely separate ways. When you set the property hibernate.show_sql to true, it tells Hibernate to write generated SQL to stdout. No logging framework is involved in this in any way. That's why you should pretty much never use it. Just remove that property from your config, and the SQL in the Tomcat console will go away.
The second way Hibernate writes the SQL, and the way you should use, is that it sends it to the logging framework under the org.hibernate.SQL logging category. It has no connection at all with hibernate.show_sql.
As an additional tidbit, in case you don't know, Hibernate also logs all values bound to parameters of the prepared statements using the org.hibernate.type category. This is something you can't get with hibernate.show_sql, so using Hibernate's logging instead of show_sql is both more flexible and more informative.