# Enabling HugePage for PostgreSQL

> Enabling HugePage for PostgreSQL to reduce memory fragmentation and improve performance.

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LLMS index: [llms.txt](/llms.txt)

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> Use `node_hugepage_count` and `node_hugepage_ratio` or `/pg/bin/pg-tune-hugepage`

If you plan to enable HugePages, consider using [`node_hugepage_count`](/docs/node/param#node_hugepage_count) and [`node_hugepage_ratio`](/docs/node/param#node_hugepage_ratio), and apply with `./node.yml -t node_tune`.

HugePages have pros and cons for databases. The advantage is that memory is managed exclusively, eliminating concerns about being reallocated and reducing database OOM risk. The disadvantage is that it may negatively impact performance in certain scenarios.

Before PostgreSQL starts, you need to allocate **enough** huge pages. The wasted portion can be reclaimed using the `pg-tune-hugepage` script, but this script is only available for PostgreSQL 15+.

If your PostgreSQL is already running, you can enable huge pages using the following method (PG15+ only):

```bash
sync; echo 3 > /proc/sys/vm/drop_caches   # Flush disk, release system cache (be prepared for database perf impact)
sudo /pg/bin/pg-tune-hugepage             # Write nr_hugepages to /etc/sysctl.d/hugepage.conf
pg restart <cls>                          # Restart postgres to use hugepage
```