Postgresql

The EAV schema is why most Magento migrations fail. It looks manageable from the outside: products stored across catalog_product_entity, catalog_product_entity_varchar, catalog_product_entity_int, catalog_product_entity_decimal, catalog_product_entity_datetime, and catalog_product_entity_text. Six tables, straightforward ETL job, done in a weekend. Then you discover that attribute_id = 75 means “product name” in your Magento instance and “color” in your staging instance. Every attribute ID is generated at install time and differs between environments. Any ETL script that hardcodes attribute IDs will produce corrupted data in production. ...

Prerequisite: Part 4 of the System Design Masterclass. Read Part 3: Caching Strategies to understand the cache layer before examining storage. Answer-first: Database sharding distributes data horizontally across independent partitions (shards) based on a shard key, reducing write contention and enabling linear storage growth. Choosing the wrong shard key leads to hot spots that can be worse than no sharding at all. Vertical vs Horizontal Scaling — When to Switch? Answer-first: Vertical scaling (scale-up) increases resources on a single server — simple but has a hard physical ceiling and non-linear cost growth. Horizontal scaling (scale-out) adds more servers — no theoretical ceiling, linear cost, but significantly higher operational complexity. ...

Answer-first: Attempting to simultaneously write inventory updates to a fast cache (Redis) and a relational database (PostgreSQL) creates the dual-write problem. If one system fails, data diverges. Furthermore, synchronous SELECT FOR UPDATE queries in SQL cause massive lock queues and API timeouts. What You’ll Learn That AI Won’t Tell You Write-through caches configuration in Redis to prevent inventory drift. Lua scripting implementations in Redis that prevent double-reservations under peak load. What Is Real-Time Inventory Synchronization? Real-time inventory synchronization is the process of propagating stock count changes from the system of record (database) to all sales channels — web storefront, mobile app, WMS, ERP — in sub-second time. Instead of batch ETL jobs that run every hour, a CDC + Kafka pipeline streams every committed stock change as an event, eliminating overselling and stale stock displays. ...

Answer-first: LeaseInVietnam runs an autonomous AI pipeline that ingests, cleans, and translates rental listings. By extracting structured property attributes using LLM-based schemas, it converts raw data into high-value expat guides and property listings, serving as a high-converting B2B lead generation engine. What You’ll Learn That AI Won’t Tell You Structuring scrapers to bypass IP blocks while parsing rental data. Using LLMs to standardize unstructured rental locations into precise lat-long values. Most AI content projects are built around one question: how do I publish more? LeaseInVietnam is built around a different question: how do I make every published piece convert? ...