> For the complete documentation index, see [llms.txt](https://docs.postgresql.tw/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.postgresql.tw/14/internals/system-catalogs/pg_shmem_allocations.md).

# 51.87. pg\_shmem\_allocations

The `pg_shmem_allocations` view shows allocations made from the server's main shared memory segment. This includes both memory allocated by postgres itself and memory allocated by extensions using the mechanisms detailed in [Section 37.10.10](https://www.postgresql.org/docs/13/xfunc-c.html#XFUNC-SHARED-ADDIN).

Note that this view does not include memory allocated using the dynamic shared memory infrastructure.

#### **Table 51.88. `pg_shmem_allocations` Columns**

| <p>Column Type</p><p>Description</p>                                                                                                                                                                                                                                                                                                                           |
| -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| <p><code>name</code> <code>text</code></p><p>The name of the shared memory allocation. NULL for unused memory and <code>\<anonymous></code> for anonymous allocations.</p>                                                                                                                                                                                     |
| <p><code>off</code> <code>int8</code></p><p>The offset at which the allocation starts. NULL for anonymous allocations, since details related to them are not known.</p>                                                                                                                                                                                        |
| <p><code>size</code> <code>int8</code></p><p>Size of the allocation</p>                                                                                                                                                                                                                                                                                        |
| <p><code>allocated\_size</code> <code>int8</code></p><p>Size of the allocation including padding. For anonymous allocations, no information about padding is available, so the <code>size</code> and <code>allocated\_size</code> columns will always be equal. Padding is not meaningful for free memory, so the columns will be equal in that case also.</p> |

Anonymous allocations are allocations that have been made with `ShmemAlloc()` directly, rather than via `ShmemInitStruct()` or `ShmemInitHash()`.

By default, the `pg_shmem_allocations` view can be read only by superusers.


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