From: Tom Lane <tgl@sss.pgh.pa.us>
To: Oskari Saarenmaa <os@ohmu.fi>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org <pgsql-hackers@postgresql.org>
Subject: Re: Use pread and pwrite instead of lseek + write and read
Date: Thu, 15 Sep 2016 14:11:11 -0400
Message-ID: <5806.1473963071@sss.pgh.pa.us> (raw)
In-Reply-To: <6e2a5f2c-8f16-6711-717a-9c7cff45546f@ohmu.fi>
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Oskari Saarenmaa <os@ohmu.fi> writes:
> 17.08.2016, 22:11, Tom Lane kirjoitti:
>> I'd be more excited about this if the claimed improvement were more than
>> 1.5%, but you know as well as I do that that's barely above the noise
>> floor for most performance measurements. I'm left wondering why bother,
>> and why take any risk of de-optimizing on some platforms.
> I think it makes sense to try to optimize for the platforms that people
> actually use for performance critical workloads, especially if it also
> allows us to simplify the code and remove more lines than we add. It's
> nice if the software still works on legacy platforms, but I don't think
> we should be concerned about a hypothetical performance impact on
> platforms no one uses in production anymore.
Well, my point remains that I see little value in messing with
long-established code if you can't demonstrate a benefit that's clearly
above the noise level. We don't really know whether this change might
have adverse impacts somewhere --- either performance-wise or bug-wise ---
and for that amount of benefit I don't want to take the trouble to find
out.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, os@ohmu.fi, robertmhaas@gmail.com
Subject: Re: Use pread and pwrite instead of lseek + write and read
In-Reply-To: <5806.1473963071@sss.pgh.pa.us>
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