Selects on tables with cidr type primary keys are broken

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                        POSTGRESQL BUG REPORT TEMPLATE
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Your name        :    Lennert Buytenhek
Your email address    :    buytenh@gnu.org


System Configuration
---------------------
  Architecture (example: Intel Pentium)      : Intel Pentium II

  Operating System (example: Linux 2.0.26 ELF)     : Red Hat Linux 6.2 (custom 2.2.16 kernel)

  PostgreSQL version (example: PostgreSQL-7.0):   PostgreSQL-7.0.2

  Compiler used (example:  gcc 2.8.0)        : Binary RPM distribution for Red Hat


Please enter a FULL description of your problem:
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Selects on tables with cidr type primary keys are broken.



Please describe a way to repeat the problem.   Please try to provide a
concise reproducible example, if at all possible:
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Behold:

<quote>
test=# \d jobschedule
      Table "jobschedule"
 Attribute |  Type   | Modifier
-----------+---------+----------
 prefix    | cidr    | not null
 interval  | integer |
Index: jobschedule_pkey

test=# select * from jobschedule;
     prefix     | interval
----------------+----------
 132.229.230/24 |  2592000
 132.229.231/24 |  2592000
 132.229.232/24 |  2592000
 132.229.12/24  |  2592000
 132.229.50/24  |  2592000
 132.229.52/24  |  2592000
 132.229.93/24  |  2592000
 132.229.95/24  |  2592000
(8 rows)

test=# explain select * from jobschedule where prefix='132.229.230/24';
NOTICE:  QUERY PLAN:

Index Scan using jobschedule_pkey on jobschedule  (cost=0.00..8.14 rows=10 width=16)

EXPLAIN
test=# select * from jobschedule where prefix='132.229.230/24';
 prefix | interval
--------+----------
(0 rows)
</quote>

If I recreate the table without prefix being a primary key, the selects
are planned as sequential scans and magically start working again.



If you know how this problem might be fixed, list the solution below:
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Eeeh.. not really. I haven't really had time yet to delve into the
PostgreSQL codebase.... :(