The Problem
Our client's dashboard was loading in 2+ seconds. The PostgreSQL database had grown to 50 million rows, and queries that were once fast had become painfully slow.
Root Cause Analysis
Using EXPLAIN ANALYZE, we identified three critical bottlenecks:
- Missing composite indexes on frequently joined columns
- Sequential scans on large tables due to outdated statistics
- N+1 query patterns in the ORM layer
The Solution
- Created targeted composite indexes reducing scan time by 95%
- Implemented Redis caching layer for frequently accessed aggregations
- Rewrote critical queries using CTEs and materialized views
- Set up pg_stat_statements monitoring for ongoing optimization
Results
- Query times dropped from 2s to 20ms (100x improvement)
- Database CPU utilization reduced by 60%
- Application could handle 4x more concurrent users