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The original implementation of ELSIF in plpgsql converted the construct into nested simple IF statements. This was prone to stack overflow with long ELSIF lists, in two different ways. First, it's difficult to generate the parsetree without using right-recursion in the bison grammar, and that's prone to parser stack overflow since nothing can be reduced until the whole list has been read. Second, we'd recurse during execution, thus creating an unnecessary risk of execution-time stack overflow. Rewrite so that the ELSIF list is represented as a flat list, scanned via iteration not recursion, and generated through left-recursion in the grammar. Per a gripe from Håvard Kongsgård.
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/.