Schema Partitioning

title: Partition Large Tables for Better Performance impact: MEDIUM-HIGH impactDescription: 5-20x faster queries and maintenance on large tables tags: partitioning, large-tables, time-series, performance

Partition Large Tables for Better Performance

Partitioning splits a large table into smaller pieces, improving query performance and maintenance operations.

Incorrect (single large table):

create table events (
  id bigint generated always as identity,
  created_at timestamptz,
  data jsonb
);

-- 500M rows, queries scan everything
select * from events where created_at > '2024-01-01';  -- Slow
vacuum events;  -- Takes hours, locks table

Correct (partitioned by time range):

create table events (
  id bigint generated always as identity,
  created_at timestamptz not null,
  data jsonb
) partition by range (created_at);

-- Create partitions for each month
create table events_2024_01 partition of events
  for values from ('2024-01-01') to ('2024-02-01');

create table events_2024_02 partition of events
  for values from ('2024-02-01') to ('2024-03-01');

-- Queries only scan relevant partitions
select * from events where created_at > '2024-01-15';  -- Only scans events_2024_01+

-- Drop old data instantly
drop table events_2023_01;  -- Instant vs DELETE taking hours

When to partition:

Tables > 100M rows
Time-series data with date-based queries
Need to efficiently drop old data

Reference: Table Partitioning