mirror of
https://github.com/postgres/postgres.git
synced 2025-07-27 12:41:57 +03:00
9515299485
The previous coding always stored variable values as strings, doing conversion on-the-fly when a numeric value was needed or a number was to be assigned. This was a bit inefficient and risked loss of precision for floating-point values. The precision aspect had been hacked around by printing doubles in "%.18e" format, which is ugly and has machine-dependent results. Instead, arrange to preserve an assigned numeric value in the original binary numeric format, converting to string only when and if needed. When we do need to convert a double to string, convert in "%g" format with DBL_DIG precision, which is the standard way to do it and produces the least surprising results in most cases. The implementation supports storing both a string value and a numeric value for any one variable, with lazy conversion between them. I also arranged for lazy re-sorting of the variable array when new variables are added. That was mainly to allow a clean refactoring of putVariable() into two levels of subroutine, but it may allow us to save a few sorts. Discussion: <9188.1462475559@sss.pgh.pa.us>
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. 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/.