Depends on whether you have access to the underlying system - postgres queries run in processes per-query so you can renice the process, or you can do similar things in C with extensions.

But not out of the box or on something like RDS - then your best bet is to write a script or function that uses sleep or pg_sleep to wait between calls to the database - I tend to do it in the database itself by using `CREATE FUNCTION` to write it, but depending on your comfort with postgres it may be better to do it in a scripting language or shell script (as in the parent article using a background job)