Re: Another bug introduced by fastpath patch - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Another bug introduced by fastpath patch
Date
Msg-id 20131128153529.GV31748@awork2.anarazel.de
Whole thread Raw
In response to Re: Another bug introduced by fastpath patch  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Another bug introduced by fastpath patch  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On 2013-11-28 10:31:21 -0500, Tom Lane wrote:
> The only remaining risk is that, if pointer
> fetch/store isn't atomic, we might fetch a half-updated pointer; which
> will be non-null, but not something we can use to reach the list.  Since
> we do purport to support such architectures, we'd better apply the patch.
> I'll change the comment a bit to mention this.

We do support such architectures? Don't we already assume we can store
xids atomically (c.f. GetOldestActiveTransactionId())? Do we support a
64bit arch, that has a atomic 4byte store, but not atomic 8byte stores?

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services



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