Parameter · Preset Options
shared_memory_size_in_huge_pages
Shows the number of huge pages needed for the main shared memory area. -1 means huge pages are not supported.
- Default:
-1 - Type: integer
- Range: -1 … 2147483647
- Applies: Read-only
In plain words
How many huge pages the main shared memory would need: shared_memory_size divided by the huge page size, rounded up. Use it to reserve exactly enough huge pages in the operating system.
For DBAs and operators
Added in PostgreSQL 15; -1 when huge pages are not supported on the platform or the size cannot be determined. The intended workflow (server stopped):
postgres -D $PGDATA -C shared_memory_size_in_huge_pages # e.g. 75
sysctl -w vm.nr_hugepages=80 # a little head-room, persist in sysctl.conf
# start PostgreSQL, then
SHOW huge_pages_status; -- PG17+: on?Recompute whenever you change shared_buffers, max_connections or huge_page_size.
How to change it
Fixed when PostgreSQL was built or the cluster was initialised. You can only read it.
See it in context
Related parameters
shared_memory_size huge_pages huge_pages_status huge_page_size