PostgreSQL 18 ← 17
← Catalog atlas / pg_shmem_allocations
SYSTEM VIEW · System view
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 PostgreSQL itself and memory allocated by extensions using the mechanisms detailed in Section 36.10.11. Note that this view does not include memory allocated using the dynamic shared memory infrastructure.
Checked column by column against a PostgreSQL 18.6 instance · Raw measurement record ↗
Columns PostgreSQL 18
pg_shmem_allocationsPostgreSQL 19 beta 3 is a preview snapshot; the structure can still change before release.
| COLUMN | TYPE | DESCRIPTION |
|---|---|---|
name |
text |
The name of the shared memory allocation. NULL for unused memory and <anonymous> for anonymous allocations. |
off |
bigintDocumented as:int8 |
The offset at which the allocation starts. NULL for anonymous allocations, since details related to them are not known. |
size |
bigintDocumented as:int8 |
Size of the allocation in bytes |
allocated_size |
bigintDocumented as:int8 |
Size of the allocation in bytes including padding. For anonymous allocations, no information about padding is available, so the size and allocated_size columns will always be equal. Padding is not meaningful for free memory, so the columns will be equal in that case also. |
Columns marked "implicit" are not included in SELECT *; some early statistics views are completed from same-version source, and the extra provenance is shown in the column description.
Common system columns 0
System attributes PostgreSQL provides, normally not expanded by SELECT *. Kept separately so they are not mixed in with ordinary columns.
| Columns | Type | attnum |
|---|
Column evolution matrix
Hover a cell for the column typePresentAdded / type or attribute changeRemoved
| COLUMN | 9.0 | 9.1 | 9.2 | 9.3 | 9.4 | 9.5 | 9.6 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
name |
– | – | – | – | – | – | – | – | – | – | |||||||
off |
– | – | – | – | – | – | – | – | – | – | |||||||
size |
– | – | – | – | – | – | – | – | – | – | |||||||
allocated_size |
– | – | – | – | – | – | – | – | – | – |
9.0 is the coverage baseline; a column already present in the baseline is not marked as added. The matrix aligns columns by name, so a rename appears as the old column removed and a new column added.
Evolution timeline
Changes between adjacent majorsPostgreSQL 17 ← 16
PostgreSQL 16 ← 15
PostgreSQL 15 ← 14
PostgreSQL 14 ← 13
PostgreSQL 13 ← 12Catalog added
Compare any two versions
Pick two versions to see added, removed, and retyped columns. The interactive comparison needs JavaScript; the evolution timeline reads fine without it.