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c89510431a
This fixes a poorly written integer comparison function which was performing subtraction in an attempt to return a negative value when a < b and a positive value when a > b, and 0 when the values were equal. Unfortunately that didn't always work correctly due to two's complement having the INT_MIN 1 further from zero than INT_MAX. This could result in an overflow and cause the comparison function to return an incorrect result, which would result in the binary search failing to find the value being searched for. This could cause poor selectivity estimates when the statistics stored the value of INT_MAX (2147483647) and the value being searched for was large enough to result in the binary search doing a comparison with that INT_MAX value. Author: Chao Li <li.evan.chao@gmail.com> Reviewed-by: David Rowley <dgrowleyml@gmail.com> Discussion: https://postgr.es/m/CAEoWx2ng1Ot5LoKbVU-Dh---dFTUZWJRH8wv2chBu29fnNDMaQ@mail.gmail.com Backpatch-through: 14
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: https://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. 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 https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.