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boringSQL stands for core belief: truly reliable tech stack. Databases? They've been around for decades and they're battle-tested. SQL? Over 50 years old and still one of the most in-demand programming languages^[1].

PostgreSQL is a universe of its own - decades-tested, still the workhorse. Around it, a generation of analytical and embedded SQL engines is extending the same boring foundations: the relational model, SQL, query planners you can reason about. Master them through practical, hands-on learning that prepares you for real-world challenges.

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VACUUM at the Page Level

Watch a VACUUM cycle with pageinspect, pg_freespace, and pg_visibility: how a dead tuple loses its storage, then its index entry, then its slot, and how the freed space gets reused.

Same rows, different SUM

Same query, same rows, different SUM totals in PostgreSQL. The culprit is parallel aggregation over double precision floats, not a bug. Here is the mechanism and the fix.

The NULL in your NOT IN

A single NULL turns NOT IN into a query that silently returns zero rows, and the planner couldn't optimize around it for as long as anyone can remember, until a PostgreSQL 19 patch.

pg_stat_statements: everything it can't

Where pg_stat_statements stops short: the entries it silently evicts, the query text that can vanish, the plans and replicas it never sees, and the query store Postgres still doesn't ship.

pg_stat_statements: everything it tells you

What pg_stat_statements records and what it quietly drops: the queryid jumble that splits one query into many rows, the frozen first-seen query text, and averages that hide your p99.

TOAST: Where PostgreSQL hides big values

A heap tuple cannot cross a page boundary, yet a single jsonb column can hold a megabyte. TOAST is the trick. A pageinspect tour of pointers and chunks.

Welcome to ORDER BY jungle

Bare names and expressions in ORDER BY go through two different parsers in PostgreSQL. The boundary is one if-statement, and it shows up in odd places.

Strong views on PostgreSQL VIEWs

Views are PostgreSQL's cleanest abstraction and its most rigid. Rewrite rules, attribute numbers, and the dependency catalog turn column changes into teardowns.

HOT Updates in Postgres

Every UPDATE risks rewriting every index. HOT updates skip that by chaining tuple versions in one page. A pageinspect tour of HOT chains and fillfactor.

PostgreSQL MVCC, Byte by Byte

Two concurrent sessions, same page, different answers. An interactive tour of xmin, xmax, snapshots, and the visibility rules deciding what you see.