PostgreSQL Intermediate Guide
Download This Cheat Sheet
Enter your email to download the PDF for free.
About This Cheat Sheet
PostgreSQL Intermediate Guide is a 5-10 page guide that assumes you already know the basics and focuses on the techniques, idioms, and trade-offs that separate competent users from confident practitioners.
PostgreSQL Intermediate Guide covers PostgreSQL — the world's most advanced open-source relational database, the default choice for new applications at startups, fintechs, and enterprises alike. It is written for backend developers, database administrators, data engineers, and analysts writing SQL daily who need accurate, working syntax without wading through documentation. An 8-page guide to intermediate PostgreSQL. Covers complex joins, CTEs, recursive queries, window functions, JSONB operations, indexing strategies, EXPLAIN analysis, full-text search, and table maintenance.
Every command, flag, and pattern in this sheet has been validated against current stable releases as of 2026. Where syntax differs between distributions, versions, or platforms, both forms are shown so you can copy-paste safely regardless of the environment you are working in. The PDF is print-ready in both A4 and US Letter formats and remains free to download forever.
What's Inside the PDF
- Most-used commands grouped by task, not alphabetically, so you find what you need by intent.
- Common flag combinations with one-line comments explaining what each option actually does.
- Real-world examples that show inputs and expected outputs, not contrived hello-world snippets.
- Edge cases and gotchas that the official documentation buries on page 47.
- Print-friendly layout that works equally well on screen and on paper next to your monitor.
When to Use This Cheat Sheet
- 1Writing and tuning complex queries — joins, CTEs, window functions, lateral joins, recursive queries.
- 2Diagnosing slow queries with `EXPLAIN (ANALYZE, BUFFERS)`, `pg_stat_statements`, and `auto_explain`.
- 3Designing schemas with proper normalisation, foreign keys, indexes, and partitioning strategies.
- 4Operating production clusters — replication, backups (`pg_basebackup`, WAL-G, pgBackRest), failover, and connection pooling (PgBouncer).
- 5Migrating from MySQL, SQL Server, or Oracle while preserving data integrity and minimising downtime.
Key Concepts to Master
MVCC
Multi-Version Concurrency Control means readers never block writers and vice-versa. Old row versions are cleaned up by autovacuum — never disable it.
Indexes
B-tree is the default; GIN, GiST, BRIN, and Hash serve specialised workloads. The right index turns a 10-second query into a 10-millisecond one.
Transactions and isolation
PostgreSQL supports Read Committed (default), Repeatable Read, and Serializable isolation. Choose deliberately based on consistency requirements.
Roles and privileges
PostgreSQL has no separate "users" — only roles, which can have login capability, own objects, and inherit from other roles.
WAL and replication
Write-Ahead Logging enables crash recovery, point-in-time recovery, and streaming/logical replication to standby servers.
Pro Tips from Practitioners
- Always run `EXPLAIN (ANALYZE, BUFFERS)` on slow queries before adding indexes. Guessing leads to bloated, unused indexes.
- Enable `pg_stat_statements` and review the top 20 queries by total time weekly. Most performance problems are obvious here.
- Set `log_min_duration_statement = 500` (ms) to catch slow queries early. Combine with `log_lock_waits = on` to find blocking.
- Never `SELECT *` in application code — list columns explicitly so schema changes do not break clients silently.
- Take regular backups and test restores. An untested backup is not a backup.
Related Books for Deeper Learning
More Cheat Sheets
Interactive Linux Commands Reference
Explore 232+ commands with syntax, examples, options, and pro tips.
Frequently Asked Questions
What is the PostgreSQL Intermediate Guide?
The PostgreSQL Intermediate Guide is a free, professionally designed PDF reference covering PostgreSQL. It is curated by practitioners and validated against current stable releases as of 2026.
What level of PostgreSQL experience does this assume?
Roughly six months of regular use. You should be comfortable with the daily commands and ready to learn the patterns, trade-offs, and idioms that come with experience.
How does PostgreSQL compare to MySQL?
PostgreSQL has stricter SQL standards compliance, richer types (JSONB, arrays, ranges, geometric), better concurrency (MVCC), and more advanced features (CTEs, window functions, extensions). MySQL is simpler and historically faster for read-heavy single-row workloads, though the gap has narrowed.
What is the difference between psql and PostgreSQL?
PostgreSQL is the database server. `psql` is the interactive terminal client used to connect to and query it.
Should I use a connection pooler?
Yes, for any workload above ~50 concurrent clients. PgBouncer (transaction or statement pooling) is the standard. PostgreSQL's per-connection memory cost is high.
How do I do zero-downtime schema migrations?
Use multi-step migrations: add new columns nullable, backfill in batches, deploy code that reads/writes both, drop the old column last. Tools like pg-osc or Liquibase help orchestrate this.
Is this cheat sheet really free?
Yes, completely free. We ask for your email so we can let you know when new cheat sheets are released and to keep our spam-detection systems happy. You can unsubscribe in one click at any time.
Can I print and share this cheat sheet?
Yes — print it, pin it to your wall, share it with your team, hand it out at meetups. The only thing we ask is that you do not strip the Dargslan attribution or republish the PDF as your own work.