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Recent Decisions
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PostgreSQL selected for Payment Service
The payment system required strong transactional consistency (ACID compliance), reliable row-level locking, and native support for strict financial audit trails. MongoDB's eventual consistency model posed unacceptable risk for idempotency under high concurrency.
MongoDB was considered for faster initial document writes, and DynamoDB was evaluated for cloud-native scaling.
During the Q1 2026 payment ledger overhaul, the team evaluated whether document or relational storage best supported double-entry accounting constraints.
Payment Service was implemented using PostgreSQL with connection pooling (PgBouncer). Zero transaction anomalies recorded in production.
Recalled from Organizational Memory: Relational constraints prevent ledger discrepancies identified in INC-217.
Initial prototype utilized MongoDB for rapid document schema iteration.
Identified race conditions during concurrent refunds; mandated ACID compliance.
Final decision approved for all payment ledger services.
Active in production with PgBouncer connection pooling.