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Commit8001fe6

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Windows: use GetSystemTimePreciseAsFileTime if available
PostgreSQL on Windows 8 or Windows Server 2012 will nowget high-resolution timestamps by dynamically loading theGetSystemTimePreciseAsFileTime function. It'll fall back toto GetSystemTimeAsFileTime if the higher precision variantisn't found, so the same binaries without problems on olderWindows releases.No attempt is made to detect the Windows version. Only thepresence or absence of the desired function is considered.Craig Ringer
1 parent519b075 commit8001fe6

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3 files changed

+59
-2
lines changed

3 files changed

+59
-2
lines changed

‎src/backend/main/main.c

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@@ -260,6 +260,12 @@ startup_hacks(const char *progname)
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/* In case of general protection fault, don't show GUI popup box */
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SetErrorMode(SEM_FAILCRITICALERRORS |SEM_NOGPFAULTERRORBOX);
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#ifndefHAVE_GETTIMEOFDAY
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/* Figure out which syscall to use to capture timestamp information */
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init_win32_gettimeofday();
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#endif
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}
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#endif/* WIN32 */
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‎src/include/port.h

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@@ -328,6 +328,8 @@ extern FILE *pgwin32_popen(const char *command, const char *type);
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#ifndefHAVE_GETTIMEOFDAY
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/* Last parameter not used */
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externintgettimeofday(structtimeval*tp,structtimezone*tzp);
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/* On windows we need to call some backend start setup for accurate timing */
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externvoidinit_win32_gettimeofday(void);
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#endif
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#else/* !WIN32 */
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‎src/port/gettimeofday.c

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Original file line numberDiff line numberDiff line change
@@ -41,10 +41,59 @@ static const unsigned __int64 epoch = UINT64CONST(116444736000000000);
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#defineFILETIME_UNITS_PER_SEC10000000L
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#defineFILETIME_UNITS_PER_USEC10
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/*
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* Both GetSystemTimeAsFileTime and GetSystemTimePreciseAsFileTime share a
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* signature, so we can just store a pointer to whichever we find. This
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* is the pointer's type.
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*/
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typedefVOID (WINAPI*PgGetSystemTimeFn)(LPFILETIME);
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/* Storage for the function we pick at runtime */
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staticPgGetSystemTimeFnpg_get_system_time=NULL;
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/*
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* During backend startup, determine if GetSystemTimePreciseAsFileTime is
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* available and use it; if not, fall back to GetSystemTimeAsFileTime.
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*/
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void
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init_win32_gettimeofday(void)
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{
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/*
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* Because it's guaranteed that kernel32.dll will be linked into our
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* address space already, we don't need to LoadLibrary it and worry about
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* closing it afterwards, so we're not using Pg's dlopen/dlsym() wrapper.
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*
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* We'll just look up the address of GetSystemTimePreciseAsFileTime if
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* present.
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*
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* While we could look up the Windows version and skip this on Windows
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* versions below Windows 8 / Windows Server 2012 there isn't much point,
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* and determining the windows version is its self somewhat Windows version
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* and development SDK specific...
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*/
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pg_get_system_time= (PgGetSystemTimeFn)GetProcAddress(
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GetModuleHandle(TEXT("kernel32.dll")),
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"GetSystemTimePreciseAsFileTime");
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if (pg_get_system_time==NULL)
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{
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/*
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* The expected error from GetLastError() is ERROR_PROC_NOT_FOUND, if
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* the function isn't present. No other error should occur.
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*
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* It's too early in startup to elog(...) if we get some unexpected
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* error, and not serious enough to warrant a fprintf to stderr about
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* it or save the error and report it later. So silently fall back to
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* GetSystemTimeAsFileTime irrespective of why the failure occurred.
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*/
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pg_get_system_time=&GetSystemTimeAsFileTime;
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}
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}
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/*
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* timezone information is stored outside the kernel so tzp isn't used anymore.
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*
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* Note: this function is not for Win32 high precision timingpurpose. See
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* Note: this function is not for Win32 high precision timingpurposes. See
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* elapsed_time().
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*/
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int
@@ -53,7 +102,7 @@ gettimeofday(struct timeval * tp, struct timezone * tzp)
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FILETIMEfile_time;
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ULARGE_INTEGERularge;
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GetSystemTimeAsFileTime(&file_time);
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(*pg_get_system_time)(&file_time);
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ularge.LowPart=file_time.dwLowDateTime;
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ularge.HighPart=file_time.dwHighDateTime;
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