Supabase Advanced Troubleshooting

Overview

When basic debugging does not reveal the root cause, you need deep PostgreSQL diagnostics: pg_stat_statements to find the slowest queries by cumulative execution time, pg_locks to detect lock contention and deadlocks, pg_stat_activity to find connection leaks, RLS policy conflict analysis to diagnose silent data filtering, Edge Function cold start profiling, and Realtime channel drop investigation. This skill covers every advanced diagnostic technique with real SQL queries and createClient from @supabase/supabase-js.

When to use: Slow query investigation, lock contention causing timeouts, connection pool exhaustion from leaks, RLS policies that silently filter or conflict, Edge Functions with unpredictable latency, or Realtime subscriptions that disconnect intermittently.

Prerequisites

• Supabase project with pg_stat_statements extension enabled
• Direct database access via SQL Editor or psql
• @supabase/supabase-js v2+ installed in your project
• Supabase CLI for Edge Function logs
• Familiarity with PostgreSQL system catalogs

Instructions

Step 1: pg_stat_statements and Slow Query Analysis