From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
cc: Serge Negodyuck <petr@petrovich.kiev.ua>, pgsql-bugs@postgresql.org
Subject: Re: BUG #8673: Could not open file "pg_multixact/members/xxxx" on
 slave during hot_standby
In-reply-to: <20140606164727.GU5146@eldon.alvh.no-ip.org>
References: <E1Vq1BO-00064N-Qn@wrigleys.postgresql.org>
 <20131209142525.GA1123@awork2.anarazel.de>
 <CABKyZDFWn+ty_m88sq2j5UThowb2Qwd0125BNx_19va2Fn57dQ@mail.gmail.com>
 <20131209150345.GB1123@awork2.anarazel.de>
 <CABKyZDFRtDzcY1=sEznC2ivmcM5p1yPQvC8qLL8XLviNF2kp7A@mail.gmail.com>
 <20131209182701.GD9519@awork2.anarazel.de>
 <20140103014616.GB7035@eldon.alvh.no-ip.org>
 <CABKyZDEV49nUYJej9Hv-hPUS=VUmMt1LmVV=YW=fV5X8nKtdtw@mail.gmail.com>
 <20140606013943.GT5146@eldon.alvh.no-ip.org>
 <20140606164727.GU5146@eldon.alvh.no-ip.org>
Comments: In-reply-to Alvaro Herrera <alvherre@2ndquadrant.com>
 message dated "Fri, 06 Jun 2014 12:47:27 -0400"
Date: Fri, 06 Jun 2014 13:04:29 -0400
Message-ID: <6687.1402074269@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-bugs-owner@postgresql.org

Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> After some simplification I think it should be clearer.  Thanks Andres
> for commenting offlist.

I find this not only unreadable but a bit scary:

! 		if (offset + MAX_MEMBERS_IN_LAST_MEMBERS_PAGE < offset)

I'm worried whether some compilers might not decide that that's a
can't-happen situation, and optimize the test away entirely.  I think
Andres' proposal is probably safer (though it needs comments).

			regards, tom lane


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