Re: BUG #14210: filter by "=" constraint doesn't work when hash index is present on a column

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Peter Geoghegan <pg(at)heroku(dot)com>
Cc: Daniel Newman <dtnewman(at)gmail(dot)com>, danielnewman(at)umich(dot)edu, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-bugs <pgsql-bugs(at)postgresql(dot)org>
Subject: Re: BUG #14210: filter by "=" constraint doesn't work when hash index is present on a column
Date: 2016-06-24 21:20:45
Message-ID: 1009.1466803245@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-bugs

Peter Geoghegan <pg(at)heroku(dot)com> writes:
> On Thu, Jun 23, 2016 at 4:08 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> So the answer is that this got broken by commit 9f03ca915196dfc8,
>> which appears to have imagined that _hash_form_tuple() is just an
>> alias for index_form_tuple(). But it ain't.

> Can we add test coverage that will detect when comparetup_index_hash()
> gives wrong answers, please? It's been broken at least 2 times, that
> I'm aware of. I'll write a patch, if that helps.

I agree that we need to do something, but I'm not very clear on what
the something is. I considered inventing a debug #define that would
reduce the _h_spool threshold to the minimum workable amount (2, looks
like), but I'm not sure how much that will help. What did you have
in mind?

regards, tom lane

In response to

Responses

Browse pgsql-bugs by date

  From Date Subject
Next Message Peter Geoghegan 2016-06-24 21:56:54 Re: BUG #14210: filter by "=" constraint doesn't work when hash index is present on a column
Previous Message Peter Geoghegan 2016-06-24 21:04:52 Re: BUG #14210: filter by "=" constraint doesn't work when hash index is present on a column