Date: Sat, 5 Nov 2022 14:46:51 -0700
From: Nathan Bossart <nathandbossart@gmail.com>
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, robertmhaas@gmail.com,
	pgsql-hackers@postgresql.org
Subject: Re: thinko in basic_archive.c
Message-ID: <20221105214651.GC137360@nathanxps13>
References: 
 <CALj2ACXJjR+4qmEunj4RtBE4rGKkW8S9BLp7qfx+62sbBYkW-g@mail.gmail.com>
 <20221020.102647.746666963360821887.horikyota.ntt@gmail.com>
 <CALj2ACUi_bzt=U7Nx5A2H0i-iK3G3EeJoe7MMKiNERmj6O3A=w@mail.gmail.com>
 <20221021.141346.1491472262189507263.horikyota.ntt@gmail.com>
 <CALj2ACULgfF_W4MitGPG7iw7KQyFstVbpQiB_B3x=fJZ4jWHvQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: 
 <CALj2ACULgfF_W4MitGPG7iw7KQyFstVbpQiB_B3x=fJZ4jWHvQ@mail.gmail.com>
Archived-At: 
 <https://www.postgresql.org/message-id/20221105214651.GC137360%40nathanxps13>
Precedence: bulk

On Fri, Oct 21, 2022 at 09:30:16PM +0530, Bharath Rupireddy wrote:
> On Fri, Oct 21, 2022 at 10:43 AM Kyotaro Horiguchi
> <horikyota.ntt@gmail.com> wrote:
>> Thanks, but we don't need to wipe out the all bytes. Just putting \0
>> at the beginning of the buffer is sufficient.
> 
> Nah, that's not a clean way IMO.

Why not?  This is a commonly-used technique.  I see over 80 existing useѕ
in PostgreSQL.  Plus, your shutdown callback only checks for the first
byte, anyway.

+	if (tempfilepath[0] == '\0')
+		return;

As noted upthread [0], I think we should be cautious to only remove the
temporary file if we know we created it.  I still feel that trying to add
this cleanup logic to basic_archive is probably more trouble than it's
worth, but if there is a safe and effective way to do so, I won't object.

[0] https://postgr.es/m/20221015211026.GA1821022%40nathanxps13

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com