About Database Connection Tester

Test database connections for MySQL, PostgreSQL, SQLite with latency analysis. Part of the DevTools Surf developer suite. Browse more tools in the Developer Utilities collection.

Use Cases

• Verify database credentials and network connectivity before deploying an application
• Benchmark connection latency from multiple application server locations
• Test SSL/TLS database connection requirements in staging before production
• Diagnose intermittent connection timeouts by running repeated connection tests

Tips

• Use the connection pool settings panel — set pool size to match your expected concurrent connections rather than leaving it at the default
• The latency histogram shows P50, P95, and P99 query latencies across 100 test iterations — useful for establishing a pre-deployment performance baseline
• Toggle SSL/TLS mode and verify the connection still succeeds — many production databases require encrypted connections that dev configs skip

Fun Facts

• PostgreSQL was first released in 1996 as the successor to POSTGRES (1989). The 'post' in PostgreSQL refers to INGRES, the relational database that POSTGRES was designed to supersede, not to the word 'postal.' PostgreSQL is used by Apple, Instagram, and 40%+ of professional developers.
• MySQL was acquired by Sun Microsystems in 2008 and then by Oracle in 2010. Concerns about Oracle's stewardship led to the fork MariaDB in 2009 by MySQL's original creator, Monty Widenius. MariaDB is the default MySQL replacement in most Linux distributions.
• The concept of a connection pool was introduced to address the high cost of establishing database connections. Opening a PostgreSQL connection takes 20-100ms and creates a new OS process. Connection poolers like PgBouncer can reduce effective connection overhead by 100x.

FAQ

What is a connection pool and why is it important?

A connection pool maintains a set of open database connections ready for use by the application, avoiding the overhead of creating a new connection per request. Without pooling, a high-traffic application can overwhelm the database with connection overhead alone.

What causes 'too many connections' errors?

PostgreSQL has a max_connections setting (default: 100). Each connection consumes ~10MB of memory. Applications without connection pooling create one connection per thread, which scales poorly. Use PgBouncer (PostgreSQL) or ProxySQL (MySQL) to multiplex connections.

What SSL modes are available for database connections?

Common SSL modes: disable (no SSL), require (encrypt but don't verify certificate), verify-ca (verify CA chain), verify-full (verify CA + hostname). Production databases should use verify-full; never use disable outside of local development.