Re[2]: [HACKERS] using indexes

Hi Tom,


TGL> Jose' wrote:
>> 
>> Hello all,
>> 
>> I have a table SP with a primary key SNO,
>> I'm trying if v6.4beta2 uses indexes
>> but seems it uses indexes only with '=' operator:

regression=>> explain select unique1 from onek where unique1 < 3;
TGL> NOTICE:  QUERY PLAN:

TGL> Index Scan using onek_unique1 on onek  (cost=28.67 size=334 width=4)

>> prova=> explain select * from sp where sno = 'S1';
>> NOTICE:  QUERY PLAN:
>> Index Scan using sp_pkey on sp  (cost=0.00 size=0 width=28)
>> EXPLAIN

TGL> Looks like maybe you need to vacuum to get statistics for the optimizer?

TGL>                   - Tom


After vacuum the behavior is the same:

prova=> create table onek(unique1 int4 primary key);
NOTICE:  CREATE TABLE/PRIMARY KEY will create implicit index onek_pkey
for table onek
CREATE
prova=> insert into onek values (1);
INSERT 152858 1
prova=> insert into onek values (10);
INSERT 152859 1
prova=> explain select unique1 from onek where unique1 < 3;
NOTICE:  QUERY PLAN:

Seq Scan on onek  (cost=0.00 size=0 width=4)

EXPLAIN
prova=> vacuum;
VACUUM
prova=> explain select unique1 from onek where unique1 < 3;
NOTICE:  QUERY PLAN:

Seq Scan on onek  (cost=1.07 size=1 width=4)

EXPLAIN

PS:  What about:     select unique1 from onek where unique1 = 3 OR unique1 = 1;
      ^^                                               does it works on v6.4 ?
 
Jose'