Is there a way to set CPU affinity for PostgreSQL processes through its configuration files? - postgresql

Question

I am using PostgreSQL 9.5 with a Java 8 Application on Windows OS (System: i5 2nd Generation). I noticed that when my application is in execution, there are several PostgreSQL processes / sub-processes that are created/removed dynamically.
These PostgreSQL processes use almost all of the CPU (>95%), due to which problem arises with other applications installed at my system.
I recently came to know about CPU affinity. For the time being, I am executing PowerShell script (outside of my Java application) which checks periodically and sets the desired value of cpu affinity for all PostgreSQL processes in execution.
I am looking for a way where I don't need to execute an external script(s) and/or there is one-time configuration required.
Is there a configuration supported by PostgreSQL 9.5 through which we can set max CPU cores to be used by PostgreSQL processes?
I looked for the solution, but could not find any.

Answer 1

There is no way to set this in the PostgreSQL configuration.
But you can start your PostgreSQL server from cmd.exe with:
start /affinity 3 C:\path\to\postgresql.exe C:\path\to\data\directory
That would allow PostgreSQL to run only on the twp “first” cores.
The cores are numbered 1, 2, 4, 8, 16 and so on, and you use the sum of the cores where you want PostgreSQL to run as argument to /affinity. For example, if you only want it to run on the third and fourth core, you would use /affinity 12.
This should work, since the Microsoft documentation says:
Process affinity is inherited by any child process or newly instantiated local process.