Re: Bitmap index scans use of filters on available columns

On Sun, Nov 8, 2015 at 12:34 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Jeff Janes <jeff(dot)janes(at)gmail(dot)com> writes:
>> On Fri, Nov 6, 2015 at 7:15 PM, Tomas Vondra
>> <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
>>> I've however also noticed that all the 'like' procedures are marked as not
>>> leak proof, which is a bit unfortunate because that's the example from
>>> Jeff's e-mail that started this thread.
>
>> Is there a reason they aren't leak proof? I don't see that they have
>> side effects, or that they can throw errors. What do they leak?
>
> Huh?
>
> regression=# select 'z' like '\';
> ERROR: LIKE pattern must not end with escape character

Ah, I was only thinking of the pattern as a constant. And there is no
way to declare a function leakproof on one input but not another.

Cheers,

Jeff