Let's assume I have a SQL Server with 4 sockets with each 1 NUMA node. Each socket has 4 physical cores. There is 512 GB of memory total so each NUMA node has 128 GB of RAM.
A key table is loaded into the first NUMA node.
Let's assume we have a lot of traffic reading from that table. If all physical cores of the socket that owns the NUMA node have 100 percent CPU utilization, does that negatively influence the cost of non-local NUMA access coming from other sockets? Or on the other hand is the cost of non-local NUMA access is irrespective of how busy that socket is?
I hope my question makes sense. Please let me know if it doesn't I will try to clarify.
We had a database issue in our production server last week and some of our business processed appeared more impacted than others. We had queries with few logical reads taking more than 1 minute. We looked at overall CPU utilization which was around 60 percent. We did not look at socket specific CPU metrics. I/O metrics were average.