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scanning; GiST and GIN do not, and it seems like too much trouble to make them do so. By teaching ExecSupportsBackwardScan() about this restriction, we ensure that the planner will protect a scroll cursor from the problem by adding a Materialize node. In passing, fix another longstanding bug in the same area: backwards scan of a plan with set-returning functions in the targetlist did not work either, since the TupFromTlist expansion code pays no attention to direction (and has no way to run a SRF backwards anyway). Again the fix is to make ExecSupportsBackwardScan check this restriction. Also adjust the index AM API specification to note that mark/restore support is unnecessary if the AM can't produce ordered output.
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. Changes between all PostgreSQL releases are recorded in the file HISTORY. 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/.