Very strange postgresql behaviour - Mailing list pgsql-sql

Hi all,
  I have postgresql 7.4.2 running on debian and I have the oddest
postgresql behaviour I've ever seen.

I do the following queries:


espsm_asme=# select customer_app_config_id, customer_app_config_name
from customer_app_config where customer_app_config_id = 5929 or
customer_app_config_id = 11527 order by customer_app_config_id;

 customer_app_config_id | customer_app_config_name
------------------------+--------------------------                   5929 | INFO
(1 row)

  I do the same query but changing the order of the or conditions:


espsm_asme=# select customer_app_config_id, customer_app_config_name
from customer_app_config where customer_app_config_id = 11527 or
customer_app_config_id = 5929 order by customer_app_config_id;

 customer_app_config_id | customer_app_config_name
------------------------+--------------------------                  11527 | MOVIDOSERENA TONI 5523
(1 row)


  As you can see, the configuration 5929 and 11527 both exists, but
when I do the queries they don't appear.
  Here below you have the execution plans. Those queries use an index,
I have done reindex table customer_app_config but nothing has changed.

espsm_asme=# explain analyze select customer_app_config_id,
customer_app_config_name from customer_app_config where
customer_app_config_id = 11527 or customer_app_config_id = 5929 order by
customer_app_config_id;
                  QUERY PLAN


--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (cost=10.28..10.29 rows=2 width=28) (actual time=0.252..0.253
 
rows=1 loops=1)   Sort Key: customer_app_config_id   ->  Index Scan using pk_cag_customer_application_id,
pk_cag_customer_application_id on customer_app_config  (cost=0.00..10.27
rows=2 width=28) (actual time=0.168..0.232 rows=1 loops=1)         Index Cond: ((customer_app_config_id =
11527::numeric)OR
 
(customer_app_config_id = 5929::numeric)) Total runtime: 0.305 ms
(5 rows)

espsm_asme=# explain analyze select customer_app_config_id,
customer_app_config_name from customer_app_config where
customer_app_config_id = 5929 or customer_app_config_id = 11527 order by
customer_app_config_id;
                  QUERY PLAN


--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sort (cost=10.28..10.29 rows=2 width=28) (actual time=0.063..0.064
 
rows=1 loops=1)   Sort Key: customer_app_config_id   ->  Index Scan using pk_cag_customer_application_id,
pk_cag_customer_application_id on customer_app_config  (cost=0.00..10.27
rows=2 width=28) (actual time=0.034..0.053 rows=1 loops=1)         Index Cond: ((customer_app_config_id =
5929::numeric)OR
 
(customer_app_config_id = 11527::numeric)) Total runtime: 0.114 ms
(5 rows)
  The table definition is the following:

espsm_asme=# \d customer_app_config                  Table "public.customer_app_config"          Column          |
  Type          |     Modifiers
 
--------------------------+-----------------------+-------------------- customer_app_config_id   | numeric(10,0)
| not null customer_app_config_name | character varying(32) | not null keyword                  | character varying(43)
|application_id           | numeric(10,0)         | not null customer_id              | numeric(10,0)         | not
nullcustomer_app_contents_id | numeric(10,0)         | number_access_id         | numeric(10,0)         | prefix
          | character varying(10) | separator                | numeric(1,0)          | default 0 on_hold
 | numeric(1,0)          | not null default 0 with_toss                | numeric(1,0)          | not null default 0
number_id               | numeric(10,0)         | param_separator_id       | numeric(4,0)          | default 1
memory_timeout          | integer               | with_memory              | numeric(1,0)          | default 0
session_enabled         | numeric(1,0)          | default 0 session_timeout          | integer               | number
               | character varying(15) |
 
Indexes:    "pk_cag_customer_application_id" primary key, btree
(customer_app_config_id)    "un_cag_kwordnumber" unique, btree (keyword, number_id)    "idx_cappconfig_ccontentsid"
btree(customer_app_contents_id)    "idx_cappconfig_cusidappid" btree (customer_id, application_id)
"idx_cappconfig_customerid"btree (customer_id)    "idx_cappconfig_onhold" btree (on_hold)
"idx_cappconfig_onholdkeyw"btree (on_hold, keyword)
 
Rules:
  A lot of rules that I don't paste as matter of length.

  Do you have any idea about how I can fix this?

-- 
Arnau