PostgreSQL Architecture Overview
Explore the internal architecture of PostgreSQL, including processes, memory structures, and storage components.
PostgreSQL Architecture Overview is a free PostgreSQL Performance & Query Optimization lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the PostgreSQL Performance & Query Optimization learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
PostgreSQL's Inner Workings
To master PostgreSQL performance, you need its architecture — the processes, memory, and storage that work together to serve your data.
The Big Picture: Core Parts
PostgreSQL's architecture splits into three areas: processes that run the work, memory structures for fast access, and storage that persists data to disk.
Processes: The Postmaster
The Postmaster is PostgreSQL's central parent process. It listens for client connections and spawns a dedicated backend process for each one.
Processes: Backend Processes
Each connection gets its own backend process handling all of that client's queries — isolation so one client's work doesn't trip up another's.
Processes: Background Workers
Several background workers handle upkeep: the WAL Writer flushes the log, Autovacuum cleans dead tuples, and the Checkpointer writes dirty pages to disk.
Memory: Shared Buffers
Shared Buffers is the shared memory cache for frequently used disk blocks. Bigger cuts disk I/O, but too big wastes memory or triggers OS swapping. Check it below.
SHOW shared_buffers;Memory: Work Memory (work_mem)
work_mem is private memory per backend for sorting, hashing, and merging. Exceed it and the operation spills to disk, slowing the query. Check it below.
SHOW work_mem;Storage: Data Files & WAL
Every change hits the Write-Ahead Log (WAL) before the data files — that's what guarantees durability and crash recovery. The query below shows the current WAL LSN.
SELECT pg_current_wal_lsn();A Client's Journey
A query's journey: the Postmaster spawns a backend, which uses shared buffers and work_mem to process data, writes changes to the WAL, then returns results.
Architecture Quick Check
Which PostgreSQL process is responsible for listening for client connections and spawning new backend processes?
Recap: PostgreSQL's Core
Recap: PostgreSQL's architecture is processes (Postmaster, backends, workers), memory (shared buffers, work_mem), and storage (data files plus the WAL).
Frequently asked questions
Is the “PostgreSQL Architecture Overview” lesson free?
Yes — the full text of “PostgreSQL Architecture Overview” is free to read here on the web, and the PostgreSQL Performance & Query Optimization course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the PostgreSQL Performance & Query Optimization course, upgrade to CoddyKit PRO.
What will I learn in “PostgreSQL Architecture Overview”?
Explore the internal architecture of PostgreSQL, including processes, memory structures, and storage components. You practise PostgreSQL Performance & Query Optimization with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start PostgreSQL Performance & Query Optimization?
No prior experience is required. PostgreSQL Performance & Query Optimization on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “PostgreSQL Architecture Overview” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this PostgreSQL Performance & Query Optimization lesson?
Yes. Every PostgreSQL Performance & Query Optimization lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Understanding Database Performance Basics
- PostgreSQL Architecture Overview
- Basic Query Execution Workflow
- Reading EXPLAIN and EXPLAIN ANALYZE Output