On 3/31/25 06:54, Eden Aharoni wrote:
Hi all,
Hopefully, someone here could help us understand whats going on with our
deployment..
We are running Postgres 17.4 on AWS RDS on an ec2 instance that has:
* 32vCPU
* 128GB RAM
* gp3 with 25K IOPS and 4000MiB/s throughput
* the instance supports up to 3125GB/s of throughput.
Whenever a query fetches data from the disk (index scan, bitmap scans,
etc.) we’re reaching 23 – 30MB/s of IO Read time.
We changed our autovacuum settings to be more aggressive (0 scale factor
and 10K threshold) so our index only scans will (hopefully) read data
from the disk rarely. However, we can’t optimize all the queries to use
index-only-scan since our users can dynamically select which columns to
see and filtering.
Is this expected IO read rate? I can’t help but feel we’re missing
something here..
RDS is a black box controlled by AWS, you are going to need to reach out
to their tech support.
Thanks a lot! 😊
--
Adrian Klaver
adrian.kla...@aklaver.com
