# pg_largeobject

The `pg_largeobject` system catalog table holds the data making up ‘large objects’. A large object is identified by an OID assigned when it is created. Each large object is broken into segments or 'pages’ small enough to be conveniently stored as rows in `pg_largeobject`. 

Each row of `pg_largeobject` holds data for one page of a large object, beginning at byte offset (*pageno*`* LOBLKSIZE`) within the object. The implementation allows sparse storage: pages may be missing, and may be shorter than `LOBLKSIZE` bytes even if they are not the last page of the object. Missing regions within a large object read as zeroes.



Table 1. `pg_catalog.pg_largeobject`

| column   | type    | references | description                                                  |
| :------- | :------ | :--------- | :----------------------------------------------------------- |
| `loid`   | oid     |            | Identifier of the large object that includes this page.      |
| `pageno` | integer |            | Page number of this page within its large object (counting from zero). |
| `data`   | bytea   |            | Actual data stored in the large object. This will never be more than `LOBLKSIZE` bytes and may be less. |