Queries not using Index - Mailing list pgsql-sql

From Daryl Herzmann
Subject Queries not using Index
Date
Msg-id Pine.LNX.4.44.0207221340470.31790-100000@akrherz.agron.iastate.edu
Whole thread Raw
List pgsql-sql
Greetings,

I suppose I should have sent this to pgsql-bugs maybe?  I would appreciate 
it if anybody could help me out.  I can't figure out what is going on 
here...

snet=# select version();                          version                           
-------------------------------------------------------------PostgreSQL 7.2.1 on i686-pc-linux-gnu, compiled by GCC
2.96

snet=# \d t2002_06               Table "t2002_06"Column  |           Type           | Modifiers 
---------+--------------------------+-----------station | character varying(5)     | valid   | timestamp with time zone
|tmpf    | smallint                 | dwpf    | smallint                 | drct    | smallint                 | sknt
|real                     | pday    | real                     | pmonth  | real                     | srad    | real
                | relh    | real                     | alti    | real                     | 
 
Indexes: t2002_06_station_idx,        t2002_06_tmpf_idx

snet=# \d t2002_06_station_idx; Index "t2002_06_station_idx"Column  |         Type         
---------+----------------------station | character varying(5)

snet=# select count(valid) from t2002_06; count  
---------1513895

snet=# vacuum analyze t2002_06;
VACUUM

snet=# vacuum t2002_06;
VACUUM

snet=# explain SELECT * from t2002_06 WHERE station = 'SGLI4';
NOTICE:  QUERY PLAN:

Seq Scan on t2002_06  (cost=0.00..35379.69 rows=35564 width=47)

EXPLAIN


Shouldn't this be an index scan?  I hope that I am not doing something 
stupid, although I probably am :(  

I even just tried this

drop index t2002_06_station_idx;
vacuum analyze t2002_06;
create index t2002_06_station_idx on t2002_06(station);
vacuum analyze t2002_06;

And I still get a Seq Scan.  Augh....

Thanks, Daryl




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