Your team's payment service recently had its database connection pool size increased from 5 to 20 after experiencing connection timeouts under load. A colleague wants to know if this config change might have broken anything elsewhere. You have been asked to produce a regression scout report saved as report.md.

=============== FILE: inputs/payment-service-overview.md ===============

Payment Service Codebase Overview

Structure

• src/db/pool.js — DB connection pool (CHANGED: maxConnections 5→20)
• src/services/payment.js — payment processing, uses pool directly
• src/services/refund.js — refund processing, uses pool directly
• src/services/reporting.js — reporting queries, uses pool directly
• src/services/audit.js — audit log writes, uses pool directly
• tests/services/payment.test.js — payment service tests
• tests/services/refund.test.js — refund service tests
• tests/services/reporting.test.js — reporting service tests
• tests/services/audit.test.js — audit service tests

Change Summary

The database connection pool in src/db/pool.js had its maxConnections setting increased from 5 to 20. This was done to prevent connection timeouts during peak payment processing load.

Key Behaviors Before Change

• Pool rejected any connection request exceeding 5 concurrent connections
• Reporting service batched queries in groups of 5, assuming pool size would never exceed 5
• All services shared the same pool instance
• Under contention, requests queued and occasionally timed out

Key Behaviors After Change

• Pool now allows up to 20 concurrent connections
• Reporting service batching logic was NOT updated (still batches in groups of 5)
• Connection rejection threshold raised from 5 to 20
• Services that previously queued will now receive connections immediately =============== END FILE ===============