Date: Thu, 5 Apr 2018 10:17:48 -0300
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Michael Banck <michael.banck@credativ.de>
Cc: Magnus Hagander <magnus@hagander.net>, Tom Lane <tgl@sss.pgh.pa.us>,
	Andres Freund <andres@anarazel.de>,
	David Steele <david@pgmasters.net>,
	PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: pgsql: Validate page level checksums in base backups
Message-ID: <20180405131748.3zrjzedxmhkr445v@alvherre.pgsql>
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Michael Banck wrote:
> Hi,

> > Do we have a precedent somewhere for how we do this, or does our test
> > framework already have a way to do it? How are all the actual data
> > directories etc cleaned up?
> 
> They (and the base backups) are getting purged on success of the whole
> testsuite. So to be clear - we are not leaving behind 1 GB of disk space
> on success, but we use 1 GB of disk space during the test.

Yeah, but it means you force the OS to keep 1 GB of useless dung in
cache.  I would hope that creating 40 MB, deleting those, then creating
further 40 MB (lather, rinse, repeat) would not overall evict 1 GB from
my OS cache.  Unless the OS keeps the unlinked files in cache, which
would be stupid.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services