Re: [HACKERS] Estimation problem with a LIKE clause containing a /

On Nov 9, 2007 3:08 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> This rule works for all the locales I have installed ... but I don't
> have any Far Eastern locales installed. Also, my test cases are only
> covering ASCII characters, and I believe many locales have some non-ASCII
> letters that sort after 'Z'. I'm not sure how hard we need to try to
> cover those corner cases, though. It is ultimately only an estimate...

My opinion is that it's acceptable to fix the problem for most cases
in most locales because, as you said, it's only an estimate. We didn't
have any report of this problem for years so it seems that it's not a
common case or at least it's not common that the bad estimate leads to
noticeably bad plans.

As far as I understand what you plan to do, it doesn't seem to be
something that prevents us to fix the problem afterwards if someone
comes with an example which doesn't fit in the schema you're proposing
and has a real performance problem with it.

--
Guillaume