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From: Nathan Bossart <nathandbossart@gmail.com>
To: Dimitrios Apostolou <jimis@gmx.net>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: [PING] [PATCH v2] parallel pg_restore: avoid disk seeks when jumping short distance forward
Date: Fri, 13 Jun 2025 17:04:47 -0500
Message-ID: <aEygf8AchBk04gOA@nathan> (raw)
In-Reply-To: <5ed51587-5a24-4d79-e36e-927620d0e3a2@gmx.net>
References: <2edb7a57-b225-3b23-a680-62ba90658fec@gmx.net>
	<a7344d8f-927c-1f97-6cc0-ac630deb98c4@gmx.net>
	<c0e531f9-accc-3a93-e9e6-2cec1471f9e9@gmx.net>
	<1282067.1744651649@sss.pgh.pa.us>
	<c6bb93c1-4042-743c-096c-27c5e7c73347@gmx.net>
	<f7a23708-c336-c189-f155-4b3197bf6ea0@gmx.net>
	<aEioDuePEBRnfJYk@nathan>
	<5ed51587-5a24-4d79-e36e-927620d0e3a2@gmx.net>

On Fri, Jun 13, 2025 at 01:00:26AM +0200, Dimitrios Apostolou wrote:
> By the way, I might have set the threshold to 1MB in my program, but
> lowering it won't show a difference in my test case, since the lseek()s I
> was noticing before the patch were mostly 8-16KB forward. Not sure what is
> the defining factor for that. Maybe the compression algorithm, or how wide
> the table is?

I may have missed it, but could you share what the strace looks like with
the patch applied?

-- 
nathan





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