9bb342811b
an explicit model of rescan costs being different from first-time costs. The costing of Material nodes in particular now has some visible relationship to the actual runtime behavior, where before it was essentially fantasy. This also fixes up a couple of places where different materialized plan types were treated differently for no very good reason (probably just oversights). A couple of the regression tests are affected, because the planner now chooses to put the other relation on the inside of a nestloop-with-materialize. So far as I can see both changes are sane, and the planner is now more consistently following the expectation that it should prefer to materialize the smaller of two relations. Per a recent discussion with Robert Haas.
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/.