Re: 8.2.4 Won't Build 8.1 Functional Indexes

Chris Hoover wrote:
> Well, the one index:
> CREATE INDEX acceptedbilling_to_date

> The second index is rather stupid, it was an early index before I
> figured out how to split a timestamp.
>
> Anyway, is there a way to make the first index work? Otherwise we end
> up with a seq scan on our billing table which is very painful.

First, please do not top post:

http://www.catb.org/jargon/html/T/top-post.html

Second:

create function mydate(varchar) returns varchar AS $$ select
to_char($1::date,'YYYYMMDD'); $$ LANGUAGE SQL IMMUTABLE;

create index foobar on date_test(mydate(date));

You will need to test this, but it does allow you to create the index.

Sincerely,

Joshua D. Drake

>
> Thanks,
>
> Chris
>
>
> On 6/6/07, *Tom Lane* <tgl(at)sss(dot)pgh(dot)pa(dot)us <mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us>> wrote:
>
> Alvaro Herrera <alvherre(at)commandprompt(dot)com
> <mailto:alvherre(at)commandprompt(dot)com>> writes:
> > You can't do this because to_date and other functions are not
> immutable.
> > 8.2 seems to be more picky about this -- the date conversions of
> > timestamptz columns are dependent on the current timezone.
>
> The reason 8.2 is more picky is that the function is less immutable
> thanks to the addition of locale-dependent functionality:
> http://archives.postgresql.org/pgsql-committers/2006-11/msg00264.php
>
> I gather that the underlying column is timestamp without tz, or it would
> never have worked in 8.1 either. That being the case, these index
> definitions seem pretty darn stupid anyway --- why aren't you just
> indexing on date_trunc or a plain cast to date?
>
> regards, tom lane
>
>

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