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Re: PostgreSQL does CAST implicitely between int and adomain derived from int

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: Jean-Michel Pouré <jm(at)poure(dot)com>
Cc: <pgsql-performance(at)postgresql(dot)org>
Subject: Re: PostgreSQL does CAST implicitely between int and adomain derived from int
Date: 2009-08-27 14:01:26
Message-ID: 4A964B66020000250002A3D8@gw.wicourts.gov (view raw or flat)
Thread:
Lists: pgsql-performance
Jean-Michel Pouré<jm(at)poure(dot)com> wrote:
> Still casting.
 
For about the tenth time on the topic -- YOUR PROBLEM HAS NOTHING
WHATSOEVER TO DO WITH CASTING!  Let that go so you can look for the
real problem.
 
Just as an example, look at this closely:
 
test=# create table t2 (c1 int not null primary key);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index
"t2_pkey" for table "t2"
CREATE TABLE
test=# insert into t2 select * from generate_series(1,10000);
INSERT 0 10000
test=# vacuum analyze;
VACUUM
test=# explain analyze select count(*) from t1 where c1 between 200
and 400;
                                                      QUERY PLAN
----------------------------------------------------------------------
-------------------------------------------------
 Aggregate  (cost=12.75..12.76 rows=1 width=0) (actual
time=0.764..0.765 rows=1 loops=1)
   ->  Index Scan using t1_pkey on t1  (cost=0.00..12.25 rows=200
width=0) (actual time=0.095..0.470 rows=201 loops=1)
         Index Cond: (((c1)::integer >= 200) AND ((c1)::integer <=
400))
 Total runtime: 0.827 ms
(4 rows)
 
The type is always put in there so that you can see what it's doing;
it doesn't reflect anything which is actually taking any time.
 
Let it go.
 
-Kevin

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