# Chapter 35. Large Objects

Table of Contents

35.1. Introduction

35.2. Implementation Features

35.3. Client Interfaces

35.3.1. Creating a Large Object

35.3.2. Importing a Large Object

35.3.3. Exporting a Large Object

35.3.4. Opening an Existing Large Object

35.3.5. Writing Data to a Large Object

35.3.6. Reading Data from a Large Object

35.3.7. Seeking in a Large Object

35.3.8. Obtaining the Seek Position of a Large Object

35.3.9. Truncating a Large Object

35.3.10. Closing a Large Object Descriptor

35.3.11. Removing a Large Object

35.4. Server-Side Functions

35.5. Example Program

PostgreSQL has a large object facility, which provides stream-style access to user data that is stored in a special large-object structure. Streaming access is useful when working with data values that are too large to manipulate conveniently as a whole.

This chapter describes the implementation and the programming and query language interfaces to PostgreSQL large object data. We use the libpq C library for the examples in this chapter, but most programming interfaces native to PostgreSQL support equivalent functionality. Other interfaces might use the large object interface internally to provide generic support for large values. This is not described here.