PostgreSQL 18, released on September 25 2025, introduces developer‑focused features such as native UUID v7 generation, virtual generated columns, enhanced RETURNING clauses, automatic BUFFERS in EXPLAIN ANALYZE, and a unified pg_get_acl() permission function, all aimed at improving everyday database development.
This article explains the technical principles and best practices of multi‑engine metric management based on Apache Calcite, covering common metric management methods, implementation details of unified SQL, virtual columns, and SQL defined functions, and outlines ByteDance’s future roadmap for extending these capabilities.
This article explains the MySQL JSON data type, demonstrates how to store structured and semi‑structured data with JSON objects and arrays, shows practical table designs for user login and profiling, and details virtual columns, function indexes, and multi‑valued indexes for fast querying.
This article explains why MySQL queries that use indexes can still become slow, examines full‑index scans, index selectivity, back‑table costs, and shows how features like index condition pushdown and virtual columns can dramatically improve performance.
This article explains why using indexes in MySQL does not always prevent slow queries, analyzes full‑index scans, index selectivity, back‑table lookups, virtual columns, and provides practical optimization techniques to reduce scanned rows and improve performance.
This article explains why a MySQL query that uses an index can still become a slow query, explores the difference between index usage and execution time, and presents practical optimization techniques such as improving selectivity, reducing back‑table lookups, using index condition push‑down, and leveraging virtual columns.
MySQL 5.7 introduces generated (virtual) columns, allowing you to store computed values such as day‑of‑week without extra storage, enabling indexed queries that bypass function‑based limitations, improving read performance while avoiding the write‑time overhead and redundancy of manual columns.
This article explains how MySQL 5.7 introduced native JSON support with validity checks, performance improvements, and virtual column indexing, compares it to MariaDB's dynamic column and PostgreSQL, and provides step‑by‑step SQL examples for creating, inserting, querying, and indexing JSON data.
