Re: [HACKERS] indexes and floats - Mailing list pgsql-hackers

From Vince Vielhaber
Subject Re: [HACKERS] indexes and floats
Date
Msg-id XFMail.980804110803.vev@michvhf.com
Whole thread Raw
In response to Re: [HACKERS] indexes and floats  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On 04-Aug-98 Tom Lane wrote:

> OK, that sounds plausible.  But in my examples,
>
>       play=> explain select x from f8 where x = 500;
>       NOTICE:  QUERY PLAN:
>       Seq Scan on f8  (cost=40.00 size=100 width=8)
>
> Your explanation implies that here, the parser is converting to
>        select x from f8 where int4(x) = 500;
> which is wrong for the same accuracy-loss reasons you cite later.
> (And if that isn't what it's doing, what then?)
>
> I think it would be a good idea if someone actually dug into this
> and verified what's going on.  I have found some other cases that
> lead me to think there's more to this than we understand just yet.
> With an index on an int4 field, I get

What file(s) are these decisions actually made in?

Vince.
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