Understanding Unusual SQL Queries in AWS Performance Insights with Dropwizard and MySQL

Question

Context:

I've observed some unexpected SQL queries appearing as top entries in AWS Performance Insights, and I'm trying to understand their origin and impact.

Details:

The queries in question are:

1. SELECT @@SESSION.transaction_read_only
2. SET SQL_SELECT_LIMIT = ?
3. SET SQL_SELECT_LIMIT = DEFAULT

These queries are consistently showing up as the top three queries in AWS Performance Insights, but they are not explicitly written in my application's code. I'm using InnoDB with MySQL.

What I've Tried:

• I've reviewed my application's code and configuration files, but I couldn't find any direct references to these queries.
• I've checked the Maven dependency tree and confirmed that my application is using Tomcat's JDBC connection pool (org.apache.tomcat:tomcat-jdbc:jar:9.0.68).
• I've considered the possibility that these queries might be related to the JDBC driver or JDBI's interaction with the database, but I'm not sure how to confirm this.

Question:

• Can anyone help me understand why these specific SQL queries are appearing in AWS Performance Insights?
• Are these queries a normal part of the JDBC driver or JDBI's operation with a MySQL database?
• If these queries are potentially impacting performance, what steps can I take to investigate further or mitigate this issue?

Any insights or advice would be greatly appreciated. Thank you!