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Simon Riggs 519b0757a3 Use GetSystemTimeAsFileTime directly in win32
PostgreSQL was calling GetSystemTime followed by SystemTimeToFileTime in the
win32 port gettimeofday function. This is not necessary and limits the reported
precision to the 1ms granularity that the SYSTEMTIME struct can represent. By
using GetSystemTimeAsFileTime we avoid unnecessary conversions and capture
timestamps at 100ns granularity, which is then rounded to 1µs granularity for
storage in a PostgreSQL timestamp.

On most Windows systems this change will actually have no significant effect on
timestamp resolution as the system timer tick is typically between 1ms and 15ms
depending on what timer resolution currently running applications have
requested. You can check this with clockres.exe from sysinternals. Despite the
platform limiation this change still permits capture of finer timestamps where
the system is capable of producing them and it gets rid of an unnecessary
syscall.

The higher resolution GetSystemTimePreciseAsFileTime call available on Windows
8 and Windows Server 2012 has the same interface as GetSystemTimeAsFileTime, so
switching to GetSystemTimeAsFileTime makes it easier to use the Precise variant
later.

Craig Ringer, reviewed by David Rowley
2014-12-08 23:32:03 +09:00
config Detect PG_PRINTF_ATTRIBUTE automatically. 2014-11-23 09:34:03 -05:00
contrib Fix pg_xlogdump's calculation of full-page image data. 2014-12-05 11:40:27 +02:00
doc doc: Fix DocBook table column count declaration 2014-12-08 02:18:29 -05:00
src Use GetSystemTimeAsFileTime directly in win32 2014-12-08 23:32:03 +09:00
.dir-locals.el
.gitattributes Add functions for dealing with PGP armor header lines to pgcrypto. 2014-10-01 16:03:39 +03:00
.gitignore Add *.pot to .gitignore 2013-10-19 10:56:52 -04:00
aclocal.m4
configure Detect PG_PRINTF_ATTRIBUTE automatically. 2014-11-23 09:34:03 -05:00
configure.in Detect PG_PRINTF_ATTRIBUTE automatically. 2014-11-23 09:34:03 -05:00
COPYRIGHT Update copyright for 2014 2014-01-07 16:05:30 -05:00
GNUmakefile.in Add TAP tests for client programs 2014-04-14 21:33:46 -04:00
HISTORY Improve text of stub HISTORY file. 2014-02-12 18:16:17 -05:00
Makefile
README Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00
README.git Don't generate plain-text HISTORY and src/test/regress/README anymore. 2014-02-10 20:48:04 -05:00

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/.