796f78998e
The problem is that the function arguments are not considered as possible key candidates for index scan and so only a sequential scan is possible inside the body of a function. I have therefore made some patches to the optimizer so that indices are now used also by functions. I have also moved the plan debug message from pg_eval to pg_plan so that it is printed also for plans genereated for function execution. I had also to add an index rescan to the executor because it ignored the parameters set in the execution state, they were flagged as runtime variables in ExecInitIndexScan but then never used by the executor so that the scan were always done with any key=1. Very odd. This means that an index rescan is now done twice for each function execution which uses an index, the first time when the index scan is initialized and the second when the actual function arguments are finally available for the execution. I don't know what is the cost of an double index scan but I suppose it is anyway less than the cost of a full sequential scan, at leat for large tables. This is my patch, you must also add -DINDEXSCAN_PATCH in Makefile.global to enable the changes. Submitted by: Massimo Dal Zotto <dz@cs.unitn.it>
POSTGRES95 Data Base Management System This directory contains the 1.02 release of Postgres95. See INSTALL for the installation notes and HISTORY for the changes. We also have a WWW home page located at: http://www.ki.net/postgres95 Postgres95 is not public domain software. It is copyrighted by the University of California but may be used according to the licensing terms of the the copyright below: ------------------------------------------------------------------------ POSTGRES95 Data Base Management System Copyright (c) 1994-6 Regents of the University of California Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and this paragraph and the following two paragraphs appear in all copies. IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.