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to be less dangerous, and often faster as well. ExprState trees are not kept across transaction boundaries; this eliminates problems with resource leakage in failed transactions. But by keeping them in a per-transaction EState, we can safely arrange for a single ExprState to be shared by all the expression evaluations done in a given plpgsql function call. (Formerly it seemed necessary to create and destroy an ExprState for each exec_eval_simple_expr() call.) This saves time in any scenario where a plpgsql function executes more than one expression. Seems to be about as fast as 7.3 for simple cases, and significantly faster for functions that do a lot of calculations.
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 several language bindings, including C, Perl, Python, and Tcl, as well as a JDBC driver. The ODBC and C++ interfaces have been moved to the PostgreSQL Projects Web Site at http://gborg.postgresql.org for separate maintenance. 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 ftp://ftp.postgresql.org/pub/. For more information look at our web site located at http://www.postgresql.org/.