NICE value warning

Help
1

I am getting the below warning when starting nodes (Version 7.1)

[warning] The NICE limit should be at least 30. This system is currently configured with the limit set to 0.
Please visit System Requirements and Recommendations · SingleStore Documentation for more information.

Yet there is nothing about the NICE values on the web page provided. Could you please elaborate what this warning is about and why I should be changing the NICE value?

Thanks

2

We’re working on a documentation update to cover this. Meanwhile, you can modify /etc/security/limits to set the max nice limit to 30, so that we can change it at node start. Or, set the default nice limit to 30 on the entire machine (or machines) you’re using.

3

Thanks for the feedback. Could you provide a technical reason for the nice value to be set as such?

4

I don’t an in-depth answer for that, other than to say that we need it that way to set process priorities or limits. Stay tuned for the documentation update. FYI @clugris.

5

We need the linux nice ulimit increased so we can increase the scheduling priority of the rowstore garbage collector threads. This isn’t a strict requirement, but under high CPU utilization with a heavy write workload running the GC threads can get starved for CPU which can result in memory use increase on the cluster (deleted versions not being freed up as quickly).

6

Here’s the new documentation for this: