Skip to main content

Huge pages for Aiven for PostgreSQL®

Understand how Aiven for PostgreSQL® uses Linux huge pages to improve memory performance, and learn how to verify huge pages status on your service.

What are huge pages​

Linux manages physical memory in fixed-size units called pages. The default page size is 4 KB. Huge pages are larger memory pages that reduce memory management overhead for processes with large shared memory segments.

PostgreSQL uses huge pages for shared_buffers, which is a large shared memory area. Allocating shared buffers with huge pages reduces memory overhead compared to the default 4 KB pages. The result is more predictable query throughput and faster standby promotion during failover.

How Aiven manages huge pages​

Aiven manages huge page allocation automatically. No configuration is required on your part.

The behavior depends on the amount of RAM available to the service node:

  • Services with 8 GB RAM or more: Aiven allocates huge pages at node startup and configures PostgreSQL to use them. If allocation fails, the node restarts rather than starting without huge pages.
  • Services with less than 8 GB RAM: Huge pages are turned off. This keeps memory behavior consistent and avoids the memory pressure that huge pages can create on smaller nodes.
note

This behavior is rolling out gradually across the Aiven for PostgreSQL® fleet. Services that have not yet received the update run without dedicated huge page allocation.

When you change shared_buffers_percentage​

The shared_buffers_percentage setting controls how much of node RAM PostgreSQL allocates to shared buffers. Because shared buffers are the main consumer of huge pages, changing this setting changes the number of huge pages required.

Aiven handles this automatically. When shared_buffers_percentage changes on a large node, the platform recomputes the required huge page pool and grows it if needed before applying the new PostgreSQL configuration.

Verify huge pages status​

Connect to your PostgreSQL service and run the following queries to confirm the current huge pages configuration and status:

SHOW huge_pages;
SHOW huge_pages_status;
SHOW shared_memory_size_in_huge_pages;

The output columns mean:

ParameterDescription
huge_pagesThe requested huge pages mode. on forces huge pages, off turns them off, try requests them and falls back silently if unavailable.
huge_pages_statusThe actual runtime result: on means PostgreSQL is running on huge pages, off means it is using standard pages.
shared_memory_size_in_huge_pagesHow many huge pages PostgreSQL's shared memory segment requires.

For a service with huge_pages = on, huge_pages_status is always on. If it is off while huge_pages is on, PostgreSQL would not have started at all.

Related pages