Support

# Navigate to Supabase Dashboard
https://supabase.com/dashboard/project/YOUR_PROJECT/logs

# Filter for slow queries (>1s execution time)
Filter: "duration > 1000"

# Common culprits:
- SELECT * FROM large_table WHERE unindexed_column = 'value'
- JOINs without proper indexes
- ORDER BY on unindexed columns

-- In Supabase SQL Editor
EXPLAIN ANALYZE
SELECT * FROM users
WHERE email = 'test@example.com';

-- Look for:
-- "Seq Scan" = BAD (no index used)
-- "Index Scan" = GOOD (index used)

-- See which indexes exist and are being used
SELECT
  schemaname,
  tablename,
  indexname,
  idx_scan as times_used
FROM pg_stat_user_indexes
WHERE schemaname = 'public'
ORDER BY idx_scan ASC;

-- idx_scan = 0 means index never used (consider dropping)

-- Example: Email lookup slow
CREATE INDEX CONCURRENTLY idx_users_email
ON users(email);

-- CONCURRENTLY = no table lock during creation
-- Safe for production with active traffic

-- Check index exists
SELECT indexname, indexdef
FROM pg_indexes
WHERE tablename = 'users'
AND indexname = 'idx_users_email';

EXPLAIN ANALYZE
SELECT * FROM users
WHERE email = 'test@example.com';

-- Should now show:
-- "Index Scan using idx_users_email"
-- Execution time: <10ms (was 5000ms+)

# Vercel Analytics (if using)
- Check p95 response time improvement

# Vercel Analytics
- Verify database timeout errors decreased

# Supabase Dashboard
- Confirm slow query count dropped