What happens when you Postgres shared_buffers is too small?

Question

In the Postgres documentation, it says the parameter "shared_buffers" sets the amount of memory the database server uses for shared memory buffers. I know if this value is too high, then the database server might use too much memory than what is available, and may cause paging to occur.

However, what happens if this value is too low? Would the database just crash if it didn't have enough memory for an intensive query? Specifically, what would it lead to? High IO wait times? High CPU usage?

Answer 1

It won't crash; it may perform poorly.