launchpad-dev team mailing list archive

[Gary Poster <gary.poster@xxxxxxxxxxxxx>]

On Nov 16, 2011, at 8:58 PM, Martin Pool <mbp@xxxxxxxxxxxxxx> wrote:

> I filed this yesterday: <https://bugs.launchpad.net/launchpad/+bug/891028>
> 
> The way getUniqueInteger is implemented using both only per-thread
> uniqueness, and also counting on pseudorandom integers to be unique
> looks pretty suspicious.
> 
> It's interesting that it would now be failing consistently, and only
> on ec2.  bac did hit this much earlier this year.

The new aspect of the error state is that  this was no longer intermittent, and that it had *exactly* the same integer reliably, across ec2 and buldbot. 

I agree with your analysis that the current code should cause intermittent collisions. Reliable collisions on the same value across machines is more mysterious. 

I think bac tried the test in isolation on ec2; my impression was that it did not fail, in which case it might or might not be Lucid-related but is more clearly related to the test suite. We were on to the revision-based revert approach at that point, though. 

The mystery is probably ignorable; Robert's solutions do seem likely to make this go away. 

Gary