| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | pgsql-hackers(at)lists(dot)postgresql(dot)org,Antonin Houska <ah(at)cybertec(dot)at> |
| Subject: | Re: Atomics in localbuf.c |
| Date: | 2020-03-05 18:02:07 |
| Message-ID: | 37DE0CF6-8920-4BF1-9EF1-6F39E32A65E5@anarazel.de |
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| Lists: | pgsql-hackers |
Hi
On March 5, 2020 9:21:55 AM PST, Antonin Houska <ah(at)cybertec(dot)at> wrote:
>What's the reason to use pg_atomic...read_...() and
>pg_atomic...write_...()
>functions in localbuf.c?
>
>It looks like there was an intention not to use them
>
>https://www.postgresql.org/message-id/CAPpHfdtfr3Aj7xJonXaKR8iY2p8uXOQ%2Be4BMpMDAM_5R4OcaDA%40mail.gmail.com
>
>but the following discussion does not explain the decision to use them.
Read/write don't trigger locked/atomic operations. They just guarantee that you're not gonna read/write a torn value. Or a cached one. Since local/shared buffers share the buffer header definition, we still have to use proper functions to access the atomic variables.
Regards,
Andres
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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