Re: Reviewing freeze map code

On Thu, Jul 7, 2016 at 1:58 PM, Andres Freund <andres@anarazel.de> wrote:
> On 2016-07-07 10:37:15 -0400, Robert Haas wrote:
>> On Wed, Jul 6, 2016 at 6:06 PM, Andres Freund <andres@anarazel.de> wrote:
>> > Hm. We can't easily do that in the back-patched version; because a
>> > standby won't know to check for the flag . That's kinda ok, since we
>> > don't yet need to clear all-visible yet at that point of
>> > heap_update. But that better means we don't do so on the master either.
>>
>> Is there any reason to back-patch this in the first place?
>
> It seems not unlikely that this has caused corruption in the past; and
> that we chalked it up to hardware corruption or something. Both toasting
> and file extension frequently take extended amounts of time under load,
> the window for crashing in the wrong moment isn't small...

Yeah, that's true, but I'm having a bit of trouble imagining exactly
we end up with corruption that actually matters.  I guess a torn page
could do it.

-- 
Robert Haas
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