Re: select using regexp does not use indexscan

tgl@sss.pgh.pa.us (Tom Lane) wrote in message news:<3972.1100390524@sss.pgh.pa.us>...
> Stephan Szabo <sszabo@megazone.bigpanda.com> writes:
> > On Tue, 9 Nov 2004, carex wrote:
> >> And it works also perfectly with Gentoo.
> >> So,is this a typical "Redhat Enterprise" problem ?
> >> Or do I overlook something ??
>  
> > IIRC, in 7.3.x, index scans are only considered in "C" locale for
> > regexp/LIKE. In 7.4.x, non-"C" locale databases can use a special
> > index of a different opclass (<typename>_pattern_ops I believe).
> 
> Not sure if this answer was explicit enough, so: evidently the database
> was initdb'd in "C" locale on Gentoo, but in some other locale on Red Hat.
> The only "typical Red Hat problem" is that they are more enthusiastic
> about setting up non-C default locales than some other distros.
> 
>             regards, tom lane
> 
> ---------------------------(end of broadcast)---------------------------

Thank you so much.
It is indeed clearer now.

So I did an initdb --locale=C -D /path/to/data
rebuild my database and started my "select" again.
I could see my index was used even when host~'^tna2';  
Thanks again.