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help / color / mirror / Atom feedFrom: Michael Paquier <[email protected]>
To: Andres Freund <[email protected]>
Cc: Xuneng Zhou <[email protected]>
Cc: pgsql-hackers <[email protected]>
Cc: Nazir Bilal Yavuz <[email protected]>
Subject: Re: Streamify more code paths
Date: Wed, 11 Mar 2026 08:29:51 +0900
Message-ID: <[email protected]> (raw)
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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
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