Re: [COMMITTERS] pgsql: Fix an O(N^2) problem in foreign key references.

On 09/15/2015 10:58 AM, Tom Lane wrote:
> I wrote:
>> Jan Wieck <jan(at)wi3ck(dot)info> writes:
>>> I'm able to reproduce that failure with CLOBBER_CACHE_ALWAYS and it
>>> definitely is caused by this commit. Do you want to back it out for the
>>> time being? Kevin is on vacation right now.
>
>> I'll take a look today, and either fix it if I can find the problem
>> quickly or back it out.
>
> The answer is "back it out", because this patch is fundamentally and
> irretrievably broken. You can't just clobber the hashtable like that,
> because there are very possibly active uses of hashtable entries in
> outer function call levels.

Ok.

Would it be appropriate to use (Un)RegisterXactCallback() in case of
detecting excessive sequential scanning of that cache and remove all
invalid entries from it at that time?

Regards, Jan

--
Jan Wieck
Senior Software Engineer
http://slony.info