On Tue, Mar 10, 2026 at 07:04:37PM -0400, Andres Freund wrote:
> It might be a good idea to run the benchmarks with debug_io_direct=data.
> That'll make them very slow, since the write side doesn't yet use AIO and thus
> will do a lot of synchronous writes, but it should still allow to evaluate the
> gains from using read stream.
Ah, thanks for the tip. I'll go try that.
> The other thing that's kinda important to evaluate read streams is to test on
> higher latency storage, even without direct IO. Many workloads are not at all
> benefiting from AIO when run on a local NVMe SSD with < 10us latency, but are
> severely IO bound when run on a cloud storage disk with 0.5ms - 4ms latency.
My previous run was on a cloud instance, I don't have access to a SSD
with this amount of latency locally.
One thing that was standing on is the bloom bitmap case that was
looking really nice for a large number of rows, so I have applied
this part. The rest is going to need a bit more testing to build more
confidence, as far as I can see.
--
Michael
