11th October 2018: PostgreSQL 11 RC 1 Released!
Supported Versions: Current (10) / 9.6 / 9.5 / 9.4 / 9.3
Development Versions: 11 / devel
Unsupported versions: 9.2 / 9.1 / 9.0 / 8.4 / 8.3 / 8.2

31.1. Introduction

All large objects are placed in a single system table called pg_largeobject. PostgreSQL also supports a storage system called "TOAST" that automatically stores values larger than a single database page into a secondary storage area per table. This makes the large object facility partially obsolete. One remaining advantage of the large object facility is that it allows values up to 2 GB in size, whereas TOASTed fields can be at most 1 GB. Also, large objects can be randomly modified using a read/write API that is more efficient than performing such operations using TOAST.