[7.3.3] select with stable function not being optimized to index scan

Your name        : Barrie Slaymaker
Your email address    : barries@slaysys.com


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

  Operating System (example: Linux 2.0.26 ELF)     : WinXP+cygwin

  PostgreSQL version (example: PostgreSQL-7.3.3):   PostgreSQL-7.3.3

  Compiler used (example:  gcc 2.95.2)        :


Please enter a FULL description of your problem:
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Stable functions aren't elevated to index scans.



Please describe a way to repeat the problem.   Please try to provide a
concise reproducible example, if at all possible:=20
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interchange=3D# create or replace function int8foo() returns int8 as=20
'BEGIN RETURN 1; END' language 'plpgsql' stable; CREATE FUNCTION mydb=3D#=
=20
explain select * from ann where fax_key =3D int8foo();
                       QUERY PLAN
---------------------------------------------------------
 Seq Scan on ann  (cost=3D0.00..2524.55 rows=3D8 width=3D1012)
   Filter: (fax_key =3D int8foo())
(2 rows)

mydb=3D# explain select * from ann where fax_key =3D 1;
                                   QUERY PLAN=20
---------------------------------------------------------------------------=
-----
 Index Scan using ann_fax_key_index on ann (cost=3D0.00..3.11 rows=3D7=20
width=3D1012)
   Index Cond: (fax_key =3D 1)
(2 rows)

mydb=3D# create or replace function int8foo() returns int8 as 'select=20
1::int8' language 'sql' stable; CREATE FUNCTION mydb=3D# explain select *=
=20
from ann where fax_key =3D int8foo();
                       QUERY PLAN
---------------------------------------------------------
 Seq Scan on ann  (cost=3D0.00..2524.55 rows=3D8 width=3D1012)
   Filter: (fax_key =3D int8foo())
(2 rows)
mydb=3D#



If you know how this problem might be fixed, list the solution below:
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If you know how this problem might be fixed, list the solution below:
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