Jeff Janes <jeff.ja...@gmail.com> writes:
> On Wed, May 23, 2012 at 2:21 PM, Tom Lane <t...@sss.pgh.pa.us> wrote:
>> However, I remain unsatisfied with this idea as an explanation for the
>> behavior you're seeing. In the first place, that race condition window
>> ought not be wide enough to allow failure probabilities as high as 10%.
>> In the second place, that code has been like that for a long while,
>> so this theory absolutely does not explain why you're seeing a
>> materially higher probability of failure in HEAD than 9.1. There is
>> something else going on.
> After a while trying to bisect the behavior, I decided it was a mug's
> game. Both arms of the race (the firing of archive_command and the
> engineered crash) are triggered indirectly be the same event, the
> start of a checkpoint. Small changes in the code can lead to small
> changes in the timing which make drastic changes in how likely it is
> that the two arms collide exactly at the vulnerability.
Ah. OK, that sounds more plausible than "it just happened".
> So my test harness is an inexplicably effective show-case for the
> vulnerability, but it is not the reason the vulnerability should be
> fixed.
Agreed.
regards, tom lane
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