Database

pg_partman: partition management

pg_partman is a Postgres extension that automates the creation and maintenance of partitions for tables using Postgres native partitioning.

Enable the extension#

To enable pg_partman, create a dedicated schema for it and enable the extension there.

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create schema if not exists partman;
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create extension if not exists pg_partman with schema partman;

Create a partitioned table#

pg_partman requires your parent table to already be declared as a partitioned table.

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create table public.messages (
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  id bigint generated by default as identity,
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  sent_at timestamptz not null,
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  sender_id uuid,
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  recipient_id uuid,
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  body text,
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  primary key (sent_at, id)
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)
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partition by range (sent_at);

Set up partitioning#

You configure the parent table using partman.create_parent(). The function takes an ACCESS EXCLUSIVE lock briefly while it creates the initial partitions.

Time-based partitions#

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select partman.create_parent(
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  p_parent_table := 'public.messages',
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  p_control := 'sent_at',
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  p_type := 'range',
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  p_interval := '7 days',
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  p_premake := 7,
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  p_start_partition := '2025-01-01 00:00:00'
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);

Integer-based partitions#

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create table public.events (
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  id bigint generated by default as identity,
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  inserted_at timestamptz not null default now(),
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  payload jsonb,
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  primary key (id)
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)
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partition by range (id);
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select partman.create_parent(
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  p_parent_table := 'public.events',
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  p_control := 'id',
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  p_type := 'range',
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  p_interval := '100000'
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);

Running maintenance#

It’s important to call pg_partman maintenance regularly so future partitions are pre-created and retention policies are applied.

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call partman.run_maintenance_proc();

To automate this, schedule it using pg_cron.

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create extension if not exists pg_cron;
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select
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  cron.schedule('@hourly', $$call partman.run_maintenance_proc()$$);

Resources#