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Prior to this, we only considered a full sort on the cheapest input path and uniquifying any path which was already sorted in the required sort order. Here we adjust create_final_distinct_paths() so that it also adds an Incremental Sort path on any path which has presorted keys. Additionally, this adjusts the parallel distinct code so that we now consider sorting the cheapest partial path and incrementally sorting any partial paths with presorted keys. Previously we didn't consider any sorting for parallel distinct and only added a unique path atop any path which had the required pathkeys already. Author: David Rowley Reviewed-by: Richard Guo Discussion: https://postgr.es/m/CAApHDvo8Lz2H=42urBbfP65LTcEUOh288MT7DsG2_EWtW1AXHQ@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. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.