pg_column_tetris

pg_column_tetris : Enforce optimal column alignment to minimize row padding

Overview

Packages

Source

pig build pkg pg_column_tetris;		# build rpm/deb

Install

Make sure PGDG and PIGSTY repo available:

pig repo add pgsql -u   # add both repo and update cache

Install this extension with pig:

pig install pg_column_tetris;		# install via package name, for the active PG version

pig install pg_column_tetris -v 18;   # install for PG 18
pig install pg_column_tetris -v 17;   # install for PG 17
pig install pg_column_tetris -v 16;   # install for PG 16
pig install pg_column_tetris -v 15;   # install for PG 15
pig install pg_column_tetris -v 14;   # install for PG 14

Create this extension with:

CREATE EXTENSION pg_column_tetris CASCADE; -- requires plpgsql

Usage

Sources:

• Project README
• Extension control file
• Version 0.1.0 SQL implementation

pg_column_tetris 0.1.0 is a pure-SQL extension for PostgreSQL 14 through 18. An event trigger estimates alignment padding after CREATE TABLE and can warn about or reject inefficient column order. It also provides inspection and rewrite-suggestion functions.

Inspect and choose enforcement

The default mode is warn; strict rejects a newly created table that the estimator considers suboptimal, and off disables the event-trigger check.

CREATE EXTENSION pg_column_tetris;

SELECT column_tetris.mode();
SELECT * FROM column_tetris.check('public.measurement'::regclass);
SELECT column_tetris.padding_wasted('public.measurement'::regclass);

SELECT column_tetris.set_mode('warn');

Use column_tetris.exclude() for tables that must not be checked. Temporary and system tables are skipped, and the event trigger checks table creation rather than every later alteration.

Treat estimates and rewrites as advisory

The estimator models tuple headers and type alignment, but it cannot fully predict real storage for null bitmaps, variable-length or toasted values, compression, and workload-specific row populations. A reported byte saving is therefore a design signal, not measured disk reclamation.

column_tetris.suggest_rewrite() returns a migration script; it does not preserve every foreign key, index, trigger, or default. The generated sequence renames the original table, creates and copies a replacement, and drops the old table, which can require an exclusive lock and downtime. Never execute that output without reviewing dependent objects, privileges, identity and sequence behavior, replication, rollback, and a realistic staging rehearsal. Column order can also be part of application contracts such as positional inserts and row decoding.