Why MySQL is using vSWAP and do not free it while there is free RAM?

It was using like 60%+ vSWAP for many days and after MySQL restart, it was freed. How can i make it free vSWAP when RAM is FREE?

Is there any way to see which exact mysql data are in SWAP i mean so i can tweak proper mysql configuration variables or see which queries are the cause of the data in the SWAP? PS: mysqltuner already used.

 

vm.swappiness is likely what is causing this.

You can see the current value by utilizing the below command.

sysctl -a | grep swap

Code (markup):

Although higher values can improve performance in some workloads, low values are recommended for database servers. https://access.redhat.com/documenta...rformance_Tuning_Guide/s-memory-tunables.html

 

@samirj09
Thx for advice! If anyone curious, i had/have it like this:
# sysctl -a|grep swap
vm.swappiness = 10
vm.prune_pswap = 0