On 12/06/17 16:12, Andres Freund wrote:
>
>> The datasets I shared are somewhat extreme in the sense that there are
>> many contiguous sequences of hash values, but it only takes one such
>> sequence with at least SH_GROW_MAX_MOVE values to trigger the issue. So
>> the hash table may still be perfectly fine for most keys, and only
>> slightly slower for the keys in the sequence.
>
> Meh, we're talking about adversarial attacks here.
Hmmmmm...
I found this problem when I dropped 10.1 into a test environment to see
what would happen. There was no deliberate attempt to break anything.
-- todd