Category: Linux

Umair Shahid explains the value of huge pages when running PostgreSQL:

Huge pages are a Linux kernel feature that allocates larger memory pages (typically 2 MB or 1 GB instead of the normal 4 KB). PostgreSQL’s shared buffer pool and dynamic shared memory segments are often tens of gigabytes, and using huge pages reduces the number of pages the processor must manage. Fewer page‑table entries mean fewer translation‑lookaside‑buffer (TLB) misses and fewer page table walks, which reduces CPU overhead and improves query throughput and parallel query performance. The PostgreSQL documentation notes that huge pages “reduce overhead … resulting in smaller page tables and less CPU time spent on memory management”

One thing I found interesting here was the advice for PostgreSQL is to disable Transparent Huge Pages whereas in SQL Server on Linux, Microsoft’s recommendation is to keep THP enabled.

Infant Arockiaraj gives people an idea of where to look:

Based on our extensive experience with customers using SQL on Linux, we have compiled a guide outlining fundamental troubleshooting steps and available tools to assist in resolving SQL on Linux issues. This guide aims to make it easier for SQL DBAs who have primarily worked on Windows operating systems over the years.

In this article, we will normalize three checks in Linux that we typically perform in Windows to start troubleshooting issues with SQL Server: 

• System logs
• SQL Server logs
• Task Manager

Note: The screenshots in the below examples are taken from RHEL and Ubuntu machines, and while the Linux flavors are different, the commands are similar in both environments. 

Click through to learn more about these steps and where you can find the files..