Re: BUG #14932: SELECT DISTINCT val FROM table gets stuck in an infinite loop

On 01/30/18 14:34, Andres Freund wrote:
> On 2018-01-30 13:57:44 -0500, Todd A. Cook wrote:
>> Out of curiosity, I then modified hashint8() as previously described.
>> With that change, run time dropped to 11 minutes (also average of 3
>> runs).
>>
>> FWIW, the data values in these sets are sort-of random (where I can't
>> explain the "sort-of" in a public forum), but strongly biased towards
>> negative infinity.  Starting again from scratch, we could probably remove
>> the bias, but we have 28-30 billion of these things collected over the
>> last 14 years (starting in PostgreSQL 7.4) and it's kinda tough to change
>> directions at this point...
> 
> FWIW, you could just create a different hash opclass and use it for
> those queries...

Hmmm, that's intriguing; I'll look into it.  Thanks! :)

-- todd