If you’ve worked with PostgreSQL long enough, you’ve probably heard this sentence before: “PostgreSQL is safe because everything is written to WAL.” It sounds reasonable. It feels reassuring. And it’s only half true. This misunderstanding — confusing WAL with actual…
Introduction One of the most confusing aspects of PostgreSQL’s logical replication is understanding the relationship between WHERE conditions in your SQL statements and REPLICA IDENTITY configuration. Many developers mistakenly believe that: “If I use a WHERE clause with specific conditions,…
Introduction pglogical is a powerful PostgreSQL extension that provides logical streaming replication using a publish/subscribe model. Developed by 2ndQuadrant (now part of EnterpriseDB), it enables selective replication of tables, columns, and rows between PostgreSQL instances, offering flexibility that traditional physical…
Introduction to Redis What is Redis? Redis (Remote Dictionary Server) is an open-source, in-memory data structure store that can be used as a database, cache, and message broker. It’s known for its exceptional speed, simplicity, and versatility. Key Characteristics Common…
Ever had that sinking feeling when you see your server’s disk space slowly vanishing? You investigate, and the trail leads you to a directory named pg_wal, filled with countless files. If this sounds familiar, you’re in the right place. Before…
Getting started with a new database system can feel like exploring a new city. You need a map to find your way around and locate key landmarks. In PostgreSQL, one of the first “landmarks” you’ll want to find is your…
You’ve run into a classic system administrator puzzle. You need to stop your PostgreSQL database, so you type the standard command: sudo systemctl stop postgresql-14. The command finishes without any errors, but when you check the running processes, the database…
When working with databases, one of the most common questions you may find yourself asking is, “How many rows are in this table?” In PostgreSQL, the answer might not be as straightforward as it seems at first glance. Although the…
PostgreSQL, as one of the most advanced and widely used relational database management systems (RDBMS), offers a range of system views that can be utilized for monitoring and diagnosing database operations. These system views provide insights into the internal state…
The max_wal_size parameter in PostgreSQL is a critical setting that directly impacts the Write-Ahead Log (WAL) system, influencing both write performance and recovery time. It controls the maximum amount of WAL data that can accumulate before a checkpoint is triggered,…
