| 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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| Lists: | pgsql-hackers |
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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