29b45dd234
- Adds `skills/postgres-best-practices/`: A new skill containing comprehensive Postgres performance optimization rules and guidelines from Supabase. - The skill includes rules for query performance, connection management, security (RLS), and schema design. - Updates `README.md` to include the new skill in the directory.
1.8 KiB
1.8 KiB
title, impact, impactDescription, tags
| title | impact | impactDescription | tags |
|---|---|---|---|
| Select Optimal Primary Key Strategy | HIGH | Better index locality, reduced fragmentation | primary-key, identity, uuid, serial, schema |
Select Optimal Primary Key Strategy
Primary key choice affects insert performance, index size, and replication efficiency.
Incorrect (problematic PK choices):
-- identity is the SQL-standard approach
create table users (
id serial primary key -- Works, but IDENTITY is recommended
);
-- Random UUIDs (v4) cause index fragmentation
create table orders (
id uuid default gen_random_uuid() primary key -- UUIDv4 = random = scattered inserts
);
Correct (optimal PK strategies):
-- Use IDENTITY for sequential IDs (SQL-standard, best for most cases)
create table users (
id bigint generated always as identity primary key
);
-- For distributed systems needing UUIDs, use UUIDv7 (time-ordered)
-- Requires pg_uuidv7 extension: create extension pg_uuidv7;
create table orders (
id uuid default uuid_generate_v7() primary key -- Time-ordered, no fragmentation
);
-- Alternative: time-prefixed IDs for sortable, distributed IDs (no extension needed)
create table events (
id text default concat(
to_char(now() at time zone 'utc', 'YYYYMMDDHH24MISSMS'),
gen_random_uuid()::text
) primary key
);
Guidelines:
- Single database:
bigint identity(sequential, 8 bytes, SQL-standard) - Distributed/exposed IDs: UUIDv7 (requires pg_uuidv7) or ULID (time-ordered, no fragmentation)
serialworks butidentityis SQL-standard and preferred for new applications- Avoid random UUIDs (v4) as primary keys on large tables (causes index fragmentation)
Reference: Identity Columns