Vico Ramdhani
Vico Ramdhani

Backend Engineer

Production Stability,
System Architecture
& Data Infrastructure

I own backend systems end-to-end — from diagnosing production incidents under pressure to designing data pipelines that connect six databases into a single reporting layer.

Production StabilitySystem ArchitectureData InfrastructurePerformance Engineering
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Measured Outcomes

Production Impact

320 → 0

Database Connections Reduced

Architecture-level pool optimization across clustered processes

16 → 0

PM2 Clusters Optimized

Right-sized based on real CPU load and throughput analysis

0+

Days Zero Production Incidents

Consecutive days of stability after architectural fix

0

Production Databases Pipelined

Orchestrated into a unified BigQuery reporting layer

Featured Case Study

Production MySQL Connection Exhaustion

Logistics system — Node.js, Sequelize, PM2 cluster mode, MySQL

Connection Architecture — Before vs After

Before — Uncontrolled
16 workers×20 pool= 320 connections
After — Optimized
8 workers×2 pool= 16 connections
Problem

Production logistics system intermittently refused new connections. MySQL returned Too Many Connections under normal traffic load. System required manual PM2 restart to recover.

Root Cause
  • Each PM2 worker instantiated a separate Sequelize instance — no shared connection singleton
  • Default pool size of 20 applied per worker — 16 × 20 = 320 connections
  • No graceful shutdown — connections leaked on process restart
Architecture Changes
  • Singleton Sequelize instance across all workers
  • Pool size reduced from 20 → 2 based on throughput profiling
  • PM2 clusters right-sized from 16 → 8 per CPU load analysis
  • SIGINT/SIGTERM handlers with kill_timeout for clean shutdown
  • Connection monitoring guard for early anomaly detection
Outcome
  • Active connections: 320 → 16 (95% reduction)
  • Too Many Connections error eliminated
  • 7+ consecutive days zero incidents post-deploy
  • Predictable resource usage — simplified capacity planning

System Ownership

Systems I've Engineered

Production systems where I owned backend architecture, performance, and operational stability.

Logistics Production System

Node.js · Sequelize · MySQL · PM2

High-availability order processing and fleet coordination

  • Resolved critical connection exhaustion — reduced 320 DB connections to 16
  • Redesigned PM2 cluster topology based on CPU and throughput profiling
  • Implemented Singleton connection pattern and graceful shutdown lifecycle
  • Deployed connection monitoring guard for anomaly detection

Fulfillment System

Golang · MySQL · REST API

Order fulfillment pipeline and warehouse integration

  • Built core fulfillment service handling order state transitions
  • Designed idempotent API contracts for reliable warehouse integration
  • Implemented structured error handling and retry mechanisms
  • Optimized query patterns for high-throughput order processing

Learning Management System

Express.js · MongoDB · REST API

Course delivery, user progress tracking, content management

  • Architected modular service layer separating business logic from transport
  • Designed document schema for flexible course and assessment structures
  • Built role-based access control for multi-tenant content delivery
  • Implemented pagination and query optimization for large dataset retrieval

Corporate Management System

Express.js · MongoDB · REST API

Internal operations, reporting, and workflow automation

  • Designed service architecture supporting multiple internal business units
  • Built configurable workflow engine for operational process automation
  • Implemented audit logging and activity tracking across modules
  • Structured API layer for integration with third-party corporate tools

Data Pipeline Architecture

Airflow · GCS · BigQuery · Looker Studio

Cross-system data orchestration and business intelligence

  • Designed DAG-based extraction pipeline across 6 production databases
  • Automated staging to Google Cloud Storage with schema validation
  • Built transformation layer in BigQuery for unified reporting datasets
  • Connected final datasets to Looker Studio dashboards for stakeholders

Data Engineering

Data Pipeline & Analytics Architecture

Designed and implemented an end-to-end data pipeline connecting 6 production databases into a unified BigQuery reporting layer — orchestrated with Apache Airflow.

Pipeline Architecture — End to End

01

Source Databases

6 production databases across logistics, fulfillment, LMS, and corporate systems

02

Apache Airflow

DAG-based orchestration scheduling automated extraction jobs per source

03

Google Cloud Storage

Raw data staged with schema validation and partitioned by extraction date

04

BigQuery

Transformation and modeling layer — cleaning, joining, and aggregating cross-system datasets

05

Looker Studio

Final reporting dashboards consumed by operations, finance, and leadership teams

Fully automated — zero manual extraction or file transfers

Cross-system integration connecting MySQL and MongoDB sources

Fault-tolerant DAGs with retry logic and failure alerting

Stakeholder-facing dashboards updated on schedule without engineering intervention

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