Optimising PostgreSQL Performance for High-Traffic Applications

PostgreSQL: Powerful but Requires Tuning

PostgreSQL is one of the most capable open-source databases available. However, default configurations are conservative — designed for compatibility, not performance. High-traffic applications require deliberate tuning of indexing, connections, and query patterns.

Index Strategy

Indexes are the single biggest performance lever. However, over-indexing slows write performance. Focus on:

• Composite Indexes: Cover your most common WHERE clause combinations.
• Partial Indexes: Index only a subset of rows (e.g., active users only).
• EXPLAIN ANALYSE: Always run this before and after adding indexes to measure real impact.

-- Find slow queries with pg_stat_statements
SELECT query, mean_exec_time, calls
FROM pg_stat_statements
ORDER BY mean_exec_time DESC
LIMIT 10;

Connection Pooling With PgBouncer

PostgreSQL creates a new process for each connection. At high concurrency, this exhausts memory. PgBouncer pools connections between application threads and the database, typically reducing connection count by 10–100x.