e3b9e44689
This removes a few static functions and replaces them with 2 functions which aim to be more reusable. The upper planner's pathkey requirements can be simplified down to operations which require pathkeys in the same order as the pathkeys for the given operation, and operations which can make use of a Path's pathkeys in any order. Here we also add some short-circuiting to truncate_useless_pathkeys(). At any point we discover that all pathkeys are useful to a single operation, we can stop checking the remaining operations as we're not going to be able to find any further useful pathkeys - they're all possibly useful already. Adjusting this seems to warrant trying to put the checks roughly in order of least-expensive-first so that the short-circuits have the most chance of skipping the more expensive checks. In passing clean up has_useful_pathkeys() as it seems to have grown a redundant check for group_pathkeys. This isn't needed as standard_qp_callback will set query_pathkeys if there's any requirement to have group_pathkeys. All this code does is waste run-time effort and take up needless space. Author: David Rowley <dgrowleyml@gmail.com> Reviewed-by: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Chao Li <li.evan.chao@gmail.com> Discussion: https://postgr.es/m/CAApHDvpbsEoTksvW5901MMoZo-hHf78E5up3uDOfkJnxDe_WAw@mail.gmail.com
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.