Re: Help with a good mental model for estimating PostgreSQL throughput

Thanks! Let's say there are 10 cores, the workload is not CPU bound, and
there is a connection pooler like pgBouncer in place. Would the number of
operations more likely be:

- 1000 ms / total ms per operation * number of cores = 1000 ms / 101 ms
* 10 = ~100
- 1000 ms / total ms per operation * number of connections = 1000 ms /
101 ms * 1000 = ~10000
- something else
- impossible to determine without more information

Best,
David

On Mon, Oct 30, 2023 at 8:46 AM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>
wrote:

> On Mon, 2023-10-30 at 08:05 -0700, David Ventimiglia wrote:
> > Can someone help me develop a good mental model for estimating
> PostgreSQL throughput?
> > Here's what I mean. Suppose I have:
> > * 1000 connections
> > * typical query execution time of 1ms
> > * but additional network latency of 100ms
> > What if at all would be an estimate of the number of operations that can
> be performed
> > within 1 second? My initial guess would be ~10000, but then perhaps I'm
> overlooking
> > something. I expect a more reliable figure would be obtained through
> testing, but
> > I'm looking for an a priori back-of-the-envelope estimate. Thanks!
>
> It depends on the number of cores, if the workload is CPU bound.
> If the workload is disk bound, look for the number of I/O requests a
> typical query
> needs, and how many of them you can perform per second.
>
> The network latency might well be a killer.
>
> Use pgBouncer with transaction mode pooling.
>
> Yours,
> Laurenz Albe
>