Re: Bitmap index scans use of filters on available columns - Mailing list pgsql-hackers

From Jeff Janes
Subject Re: Bitmap index scans use of filters on available columns
Date
Msg-id CAMkU=1w+UbxEBSvgS34CsJxxLXbn4qaKnRuKG0iGLPWZ3YtS=w@mail.gmail.com
Whole thread Raw
In response to Re: Bitmap index scans use of filters on available columns  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Sun, Nov 8, 2015 at 12:34 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Jeff Janes <jeff.janes@gmail.com> writes:
>> On Fri, Nov 6, 2015 at 7:15 PM, Tomas Vondra
>> <tomas.vondra@2ndquadrant.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



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