Re: Range Types regression failure

On 6 April 2012 22:35, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Thom Brown <thom@linux.com> writes:
>> I can't explain why I'm seeing a range type installcheck failure as I
>> don't see the same problem on the buildfarm, but out of all the tests
>> run, the range types test is the only one to fail.
>
> I can duplicate that output ordering if I force it to use indexscans,
> but it's quite unclear why it would do so by default for a six-row
> table.  Are you using weird planner cost parameters?  (I'd have expected
> such to result in a lot more diffs than this, though.)

Ah, you've nailed it.  It's performing an index-only scan:

thom@regression=# explain select * from numrange_test where nr <
numrange(-1000.0, -1000.0,'[]');                                           QUERY PLAN
--------------------------------------------------------------------------------------------------Index Only Scan using
numrange_test_btreeon numrange_test 
(cost=0.00..20.00 rows=437 width=32)  Index Cond: (nr < '[-1000.0,-1000.0]'::numrange)
(2 rows)

And you are right about my cost settings.  I have random_page_cost set
to 1.1 as I'm using an SSD.  Setting it back to 4.0 and re-running the
tests removes the issue.  My fault for swapping in my edited conf file
prior to tests.

Thanks.

--
Thom