Re: Strange behaviors with ranges

On 8/27/24 10:29, Jean-Christophe Boggio wrote:
> I have 2 very confusing behaviors when using ranges.
>
> It all started with this query:
>
>     WITH rangespaliers AS (
>         SELECT numrange( qtep1+1   , qtep2,  '[]') AS rangep FROM paliers JOIN tmp_limitcontrats
> USING(idcontrat)
> --        SELECT numrange( qtep1+1   , qtep2,  '[]') AS rangep FROM paliers WHERE idcontrat=1003
>     )
>     ,rangespaliers2 AS (
>         select *
>         FROM rangespaliers
>         WHERE rangep <> NUMRANGE(NULL, NULL) -- ERROR IS HERE
>     )
>     select * from rangespaliers2;
>
> When I run this query, I get the error "Range lower bound must be less than or equal to range upper
> bound".
>
> (a) If I comment out the line marked "ERROR IS HERE", I don't have an error (but I'm missing the
> filter of course).
>
> (b) Also, if I uncomment line 3 and comment out line 2, I get the correct behavior. Very strange
> thing is that tmp_limitcontrats has only one row which contains "idcontrat=1003".

The issue is the order-of-operations used by the planner. If I put EXPLAIN on your last query, I see:

Hash Join (cost=16.64..109.90 rows=2410 width=64)
Hash Cond: (tmp_limitcontrats.idcontrat = paliers.idcontrat)
-> Seq Scan on tmp_limitcontrats (cost=0.00..35.50 rows=2550 width=4)
-> Hash (cost=14.27..14.27 rows=189 width=12)
-> Seq Scan on paliers (cost=0.00..14.27 rows=189 width=12)
Filter: (numrange(((qtep1 + 1))::numeric, (qtep2)::numeric) <> '(,)'::numrange)

So we are applying that filter to every row in paliers, not just the one with idcontrat = 1003.

Indeed this simplified version also fails:

SELECT numrange(qtep1+1,qtep2) as rangep FROM paliers;

Yours,

--
Paul ~{:-)
pj(at)illuminatedcomputing(dot)com