Re: visibility maps

From: "Pavan Deolasee" <pavan(dot)deolasee(at)gmail(dot)com>
To: "Heikki Linnakangas" <heikki(dot)linnakangas(at)enterprisedb(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: visibility maps
Date: 2008-12-06 14:46:22
Message-ID: 2e78013d0812060646rbee1676g76e54e3c0d55d818@mail.gmail.com
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On Sat, Dec 6, 2008 at 7:57 PM, Heikki Linnakangas <
heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:

>
> Umm, what non-atomic state could the bit be in? Half-set, half-cleared? Or
> do you think that if some other bit in proximity is changed, the other bit
> would temporarily flip 0->1->0, or something like that? I don't think that
> should happen.
>
>
Since the lock is not held, the bit can be flipped while we are reading,
isn't it ? IOW, the test is not reliable is what I fear.

Thanks,
Pavan

--
Pavan Deolasee
EnterpriseDB http://www.enterprisedb.com

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