QueryLens for Java

See the SQL queries your Spring Boot endpoints really execute without leaving VS Code.

Features

• Groups Hibernate and JDBC queries by HTTP request
• Detects possible N+1 query patterns
• Displays request duration and query counts
• Scores database health across the entire debugging session
• Compares endpoints and prioritizes N+1, slow-query, and query-volume risks
• Exports a shareable Markdown health report
• Opens the Java source location behind a query
• Starts Maven and Gradle Spring Boot projects with the bundled Java agent
• Keeps trace data entirely on your machine

Getting started

1. Open a Spring Boot project in VS Code.
2. Select the QueryLens icon in the activity bar.
3. Run QueryLens: Run Spring Boot with Agent or use the play button.
4. Send a request to one of your application endpoints.
5. Expand the request in QueryLens to inspect its SQL queries.

Click a query to jump to the Java source location. Repeated queries that meet the configured threshold appear with an N+1 warning.

Tutorial

1. Open a supported project

Open the folder that contains your Spring Boot pom.xml, build.gradle, or build.gradle.kts. QueryLens searches multi-root workspaces and nested modules for Spring Boot projects.

2. Start the application

Open the QueryLens sidebar and select the play button, or run:

QueryLens: Run Spring Boot with Agent

If more than one Spring Boot module is present, select the module you want to run. QueryLens starts Maven or Gradle in a terminal and attaches its bundled Java agent. The status bar displays QueryLens ready when the local collector is listening.

3. Send an HTTP request

Call any Spring MVC endpoint using a browser, curl, Postman, Bruno, or another REST client. For example:

curl http://localhost:8080/api/purchases

4. Read the results

The request appears automatically in the QueryLens sidebar:

• Select the request to open the visual request dashboard.
• Expand the request to inspect individual SQL statements.
• A yellow N+1 item means the same normalized query crossed the configured repetition threshold.
• Select a SQL item to open the Java source line associated with the query.

Run QueryLens: Open Getting Started at any time to reopen the interactive walkthrough inside VS Code.

Database Health dashboard

After capturing one or more requests, select the graph button in the QueryLens view or run QueryLens: Open Database Health Dashboard. The dashboard ranks endpoints by a deterministic 0–100 score and turns findings into practical recommendations. Use QueryLens: Export Health Report to save the same analysis as Markdown for a pull request or team review.

Settings

• queryLens.collectorPort — local trace collector port; default 4318
• queryLens.nPlusOneThreshold — repeated-query warning threshold; default 3
• queryLens.slowQueryThresholdMs — slow-query warning threshold; default 100

Current compatibility

• Spring Boot 3
• Spring MVC
• Hibernate/JDBC
• Maven and Gradle projects
• Java 17 or newer

Privacy

The collector listens only on 127.0.0.1. QueryLens does not upload source code, SQL statements, or trace data.

Project

Source code, issues, and contribution information are available on GitHub.