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| title: pg_largeobject |
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| 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`. The amount of data per page is defined to be `LOBLKSIZE` (which is currently `BLCKSZ`/4, or typically 8K). |
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| 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. |
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| <a id="topic1__gt143898"></a> |
| <span class="tablecap">Table 1. pg\_catalog.pg\_largeobject</span> |
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| | 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. | |
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