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

On 2017-12-06 12:14:24 -0500, Tom Lane wrote:
> Checking out hashint8() on random data shows no such obvious fault.
> You've apparently got a data set that exposes a weakness in hashint8,
> but it's not very clear what that is.

It's intentionally designed to cause problems afaict:

http://archives.postgresql.org/message-id/861b9f1f-cdc0-bc49-2595-80bc39c37dc3%40blackducksoftware.com


> In any case, the hashtable code needs to not fall over in the
> presence of a lot of collisions, regardless of the exact reason
> for there being a lot.

Yes, we need to be more resilient about it. Working on a patch.

Greetings,

Andres Freund