pg_shmem_allocations_numa #
The pg_shmem_allocations_numa shows how shared
memory allocations in the server's main shared memory segment are distributed
across NUMA nodes. This includes both memory allocated by
PostgreSQL itself and memory allocated
by extensions using the mechanisms detailed in
Section 36.10.11. This view will output multiple rows
for each of the shared memory segments provided that they are spread across
multiple NUMA nodes. This view should not be queried by monitoring systems
as it is very slow and may end up allocating shared memory in case it was not
used earlier.
Current limitation for this view is that won't show anonymous shared memory
allocations.
Note that this view does not include memory allocated using the dynamic shared memory infrastructure.
When determining the NUMA node, the view touches all memory pages for the shared memory segment. This will force allocation of the shared memory, if it wasn't allocated already, and the memory may get allocated in a single NUMA node (depending on system configuration).
Tableau 53.28. pg_shmem_allocations_numa Columns
Column Type Description |
|---|
The name of the shared memory allocation. |
ID of NUMA node |
Size of the allocation on this particular NUMA memory node in bytes |
By default, the pg_shmem_allocations_numa view can be
read only by superusers or roles with privileges of the
pg_read_all_stats role.