How to Disable Transparent Huge Pages (THP) for Optimal PostgreSQL 15 Performance on a Linux Server

Disabling Transparent Huge Pages (THP) can help improve the performance of PostgreSQL by preventing potential latency spikes caused by the defragmentation process that THP performs. Here's a step-by-step guide on how to disable Transparent Huge Pages for optimal performance of your PostgreSQL server.

Step 1: Verify the Current THP Status

Before disabling THP, you can check its current status by running the following commands:

cat /sys/kernel/mm/transparent_hugepage/enabled
cat /sys/kernel/mm/transparent_hugepage/defrag

The output will show the current status of THP and whether it is enabled or disabled.

Step 2: Disable THP at Runtime

To disable THP without rebooting the server, you can run the following commands:

echo never | sudo tee /sys/kernel/mm/transparent_hugepage/enabled
echo never | sudo tee /sys/kernel/mm/transparent_hugepage/defrag

These commands will disable THP until the next reboot. To make this change permanent, follow the next steps.

Step 3: Disable THP Permanently

To disable THP permanently, you need to modify the kernel boot parameters. This can be done by editing the GRUB configuration file.

1. Edit the GRUB Configuration File

Open the GRUB configuration file in a text editor:

sudo nano /etc/default/grub

2. Modify the GRUB_CMDLINE_LINUX_DEFAULT Parameter

Find the line that starts with GRUB_CMDLINE_LINUX_DEFAULT and add transparent_hugepage=never to the list of parameters. It should look something like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash transparent_hugepage=never"

3. Update GRUB

After modifying the GRUB configuration file, update GRUB to apply the changes:

sudo update-grub

Step 4: Reboot the Server

Reboot the server to apply the changes:

sudo reboot

Step 5: Verify THP is Disabled

After the server reboots, verify that THP is disabled by running the following commands again:

cat /sys/kernel/mm/transparent_hugepage/enabled
cat /sys/kernel/mm/transparent_hugepage/defrag

The output should show that THP is set to never.

Automate the Process Using a Startup Script (Optional)

If you prefer not to modify GRUB or want to ensure that THP is disabled at every boot, you can create a startup script.

1. Create a Script to Disable THP

Create a new script file, for example, /etc/init.d/disable-thp.sh:

sudo nano /etc/init.d/disable-thp.sh

Add the following content to the script:

#!/bin/bash
### BEGIN INIT INFO
# Provides:          disable-thp
# Required-Start:    $local_fs
# Required-Stop:
# Default-Start:     2 3 4 5
# Default-Stop:
# Short-Description: Disable Transparent Huge Pages (THP)
### END INIT INFO

echo never > /sys/kernel/mm/transparent_hugepage/enabled
echo never > /sys/kernel/mm/transparent_hugepage/defrag

2. Make the Script Executable

Make the script executable:

sudo chmod +x /etc/init.d/disable-thp.sh

3. Register the Script to Run at Startup

Register the script to run at startup:

sudo update-rc.d disable-thp.sh defaults

Conclusion

Disabling Transparent Huge Pages (THP) can help improve PostgreSQL performance by reducing latency spikes caused by THP's defragmentation process. By following the steps above, you can disable THP both temporarily and permanently. Regularly monitor your PostgreSQL performance to ensure that the changes have a positive impact.