Date: Wed, 31 May 2023 08:47:12 -0500
From: Kenneth Marshall <ktm@rice.edu>
To: Sergio Rus <geiros@gmail.com>
Cc: pgsql-performance@lists.postgresql.org
Subject: Re: How to reduce latency with fast short queries in Postgresql 15.3
 on a NUMA server
Message-ID: <20230531134712.GG19068@aart.rice.edu>
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On Wed, May 31, 2023 at 02:40:05PM +0200, Sergio Rus wrote:
> Hi guys,
> 
> I've been configuring a new server and tuning Postgresql 15.3, but I'm
> struggling with a latency I'm consistently seeing with this new server when
> running fast short queries, compared to the other server.
> 
> We're running two different versions of Postgresql:
> 
> - Server A: Postgresql 9.3
> - Server B: Postgresql 15.3
> 
> Server B is the new server and is way more powerful than server A:
> 
> - Server A: 1x Intel Xeon E3-1270 3.5GHz, 2x 8GB DDR3, RAID0
> - Server B: 2x Intel Xeon Platinum 8260 2.4GHz, 4x 16GB DDR4, RAID1
> ...
> Conclusion:
> 
> As you can see, server B has 2 CPUs and is using NUMA on Linux.  And the
> CPU clock is slower on server B than server A. Maybe any of those are
> causing that latency?
> 

Hi Sergio,

This really looks like it is caused by the CPU clock speed difference.
The E3 is 1.6X faster at the base frequency. Many times that is the
trade-off when going to many more cores. Simple short will run faster on
the older CPU even though overall the new CPU has much more total
capacity.

Regards,
Ken