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the associated datatype as their equality member. This means that these opclasses can now support plain equality comparisons along with LIKE tests, thus avoiding the need for an extra index in some applications. This optimization was not possible when the pattern opclasses were first introduced, because we didn't insist that text equality meant bitwise equality; but we do now, so there is no semantic difference between regular and pattern equality operators. I removed the name_pattern_ops opclass altogether, since it's really useless: name's regular comparisons are just strcmp() and are unlikely to become something different. Instead teach indxpath.c that btree name_ops can be used for LIKE whether or not the locale is C. This might lead to a useful speedup in LIKE queries on the system catalogs in non-C locales. The ~=~ and ~<>~ operators are gone altogether. (It would have been nice to keep them for backward compatibility's sake, but since the pg_amop structure doesn't allow multiple equality operators per opclass, there's no way.) A not-immediately-obvious incompatibility is that the sort order within bpchar_pattern_ops indexes changes --- it had been identical to plain strcmp, but is now trailing-blank-insensitive. This will impact in-place upgrades, if those ever happen. Per discussions a couple months ago. |
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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/.