Author Archives: Stanislav_Panteleev

✅ When you close a connection in your code, does the connection return to the pool? Answer:Yes — that’s exactly how connection pooling works. 🔹 How it works in HikariCP (and other connection pools): When you call connection.close() on a … Continue reading →

✅ How can HikariCP help identify slow queries or mismanaged connections? Answer:HikariCP provides two main mechanisms to help you identify slow queries and mismanaged (unclosed) connections, both of which can exhaust your connection pool and degrade performance: 🔹 1. Leak … Continue reading →

✅ Does the pool always keep minimumIdle connections, and are connections above minimumIdle closed after idleTimeout? Answer:Yes — that’s exactly how it works: 🔹 HikariCP’s idle connection management works like this: The pool tries to maintain at least minimumIdle connections … Continue reading →

✅ What are some tuning strategies for HikariCP in high-concurrency environments? Answer:When your application experiences high concurrency — i.e., many simultaneous database requests — you need to carefully tune HikariCP to avoid bottlenecks or resource exhaustion. Here are key strategies: … Continue reading →

Answer:🔹 What is keepaliveTime?The keepaliveTime setting in HikariCP specifies how often idle connections should be proactively pinged (validated) to keep them alive. If a connection sits idle longer than keepaliveTime, HikariCP will run a lightweight validation (using isValid() or your … Continue reading →

HikariCP validates a connection before handing it to your application using a connection test query or JDBC-standard connection validation methods, depending on your configuration: 🔹 1. Connection test query (connectionTestQuery)You can explicitly set a lightweight SQL statement (e.g., SELECT 1) … Continue reading →

You can monitor HikariCP metrics in several ways, depending on your tech stack: 🔹 1. Built-in JMX SupportHikariCP exposes key metrics through JMX, which you can consume with tools like JConsole, VisualVM, or monitoring solutions that support JMX (e.g., Prometheus … Continue reading →

Purpose:The leakDetectionThreshold setting in HikariCP helps detect connection leaks — cases when your application borrows a connection from the pool but forgets to close it.If a connection remains open (checked out) longer than the configured threshold, HikariCP logs a stack … Continue reading →

Purpose:The idleTimeout property in HikariCP specifies how long an idle connection can stay in the pool before it’s closed. Essentially, it controls when unused connections are retired to reduce resource usage (e.g., DB connections, memory). Default:By default, idleTimeout is set … Continue reading →

In a Spring Boot project, you typically define HikariCP settings in the application.properties or application.yml file. Spring Boot auto-configures HikariCP as the default connection pool if it’s on the classpath, and you can customize it by adding properties with the … Continue reading →