fa117ee403
Add a "copy" argument to make it optional to receive a copy of caller tuple that is safe to use following a subsequent manipulating of tuplesort's state. This is a performance optimization. Most existing tuplesort_gettupleslot() callers are made to opt out of copying. Existing callers that happen to rely on the validity of tuple memory beyond subsequent manipulations of the tuplesort request their own copy. This brings tuplesort_gettupleslot() in line with tuplestore_gettupleslot(). In the future, a "copy" tuplesort_getdatum() argument may be added, that similarly allows callers to opt out of receiving their own copy of tuple. In passing, clarify assumptions that callers of other tuplesort fetch routines may make about tuple memory validity, per gripe from Tom Lane. Author: Peter Geoghegan Discussion: CAM3SWZQWZZ_N=DmmL7tKy_OUjGH_5mN=N=A6h7kHyyDvEhg2DA@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: http://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 http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.