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matching before recursing instead of after. The DFA match eliminates unworkable midpoint choices a lot faster than the recursive check, in most cases, so doing it first can speed things up; particularly in pathological cases such as recently exhibited by Michael Glaesemann. In addition, apply some cosmetic changes that were applied upstream (in the Tcl project) at the same time, in order to sync with upstream version 1.15 of regexec.c. Upstream apparently intends to backpatch this, so I will too. The pathological behavior could be unpleasant if encountered in the field, which seems to justify any risk of introducing new bugs. Tom Lane, reviewed by Donal K. Fellows of Tcl project
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/.