[PROPOSAL] Platform-native resource usage stats for Windows

diff --git a/src/include/utils/pg_rusage.h b/src/include/utils/pg_rusage.h
index 1234567..abcdefg 100644
--- a/src/include/utils/pg_rusage.h
+++ b/src/include/utils/pg_rusage.h
@@ -15,10 +15,31 @@
 
 #include <sys/resource.h>
 
+#ifdef WIN32
+typedef struct PgWin32ResourceUsage
+{
+	uint64		io_read_bytes;
+	uint64		io_write_bytes;
+	uint64		io_other_bytes;
+	uint32		io_read_ops;
+	uint32		io_write_ops;
+	size_t		working_set_size;
+	size_t		peak_working_set_size;
+	size_t		private_bytes;
+	uint32		page_fault_count;
+	uint32		handle_count;
+	uint32		thread_count;
+} PgWin32ResourceUsage;
+#endif
 
 typedef struct PGRUsage
 {
 	struct rusage ru;
 	struct timeval tv;
+#ifdef WIN32
+	PgWin32ResourceUsage win32;
+#endif
 } PGRUsage;
 
 
diff --git a/src/backend/utils/misc/pg_rusage.c b/src/backend/utils/misc/pg_rusage.c
index 2345678..bcdefgh 100644
--- a/src/backend/utils/misc/pg_rusage.c
+++ b/src/backend/utils/misc/pg_rusage.c
@@ -18,6 +18,12 @@
 
 #include "utils/pg_rusage.h"
 
+#ifdef WIN32
+#include <windows.h>
+#include <psapi.h>
+#include <tlhelp32.h>
+#endif
+
 
 /*
  * Initialize usage snapshot.
@@ -26,8 +32,87 @@ void
 pg_rusage_init(PGRUsage *ru0)
 {
 	getrusage(RUSAGE_SELF, &ru0->ru);
 	gettimeofday(&ru0->tv, NULL);
+
+#ifdef WIN32
+	{
+		HANDLE hProcess = GetCurrentProcess();
+		PROCESS_MEMORY_COUNTERS_EX memCounters;
+		IO_COUNTERS ioCounters;
+		
+		memset(&ru0->win32, 0, sizeof(PgWin32ResourceUsage));
+		
+		/* Get memory statistics */
+		memset(&memCounters, 0, sizeof(memCounters));
+		memCounters.cb = sizeof(memCounters);
+		if (GetProcessMemoryInfo(hProcess,
+								 (PROCESS_MEMORY_COUNTERS *)&memCounters,
+								 sizeof(memCounters)))
+		{
+			ru0->win32.working_set_size = memCounters.WorkingSetSize;
+			ru0->win32.peak_working_set_size = memCounters.PeakWorkingSetSize;
+			ru0->win32.private_bytes = memCounters.PrivateUsage;
+			ru0->win32.page_fault_count = memCounters.PageFaultCount;
+		}
+		
+		/* Get I/O statistics */
+		memset(&ioCounters, 0, sizeof(ioCounters));
+		if (GetProcessIoCounters(hProcess, &ioCounters))
+		{
+			ru0->win32.io_read_bytes = ioCounters.ReadTransferCount;
+			ru0->win32.io_write_bytes = ioCounters.WriteTransferCount;
+			ru0->win32.io_other_bytes = ioCounters.OtherTransferCount;
+			ru0->win32.io_read_ops = (uint32)ioCounters.ReadOperationCount;
+			ru0->win32.io_write_ops = (uint32)ioCounters.WriteOperationCount;
+		}
+		
+		/* Get handle count */
+		GetProcessHandleCount(hProcess, &ru0->win32.handle_count);
+		
+		/* Get thread count using toolhelp32 snapshot */
+		{
+			HANDLE hSnapshot;
+			THREADENTRY32 te32;
+			DWORD dwOwnerPID = GetCurrentProcessId();
+			
+			ru0->win32.thread_count = 0;
+			
+			hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
+			if (hSnapshot != INVALID_HANDLE_VALUE)
+			{
+				te32.dwSize = sizeof(THREADENTRY32);
+				
+				if (Thread32First(hSnapshot, &te32))
+				{
+					do
+					{
+						if (te32.th32OwnerProcessID == dwOwnerPID)
+							ru0->win32.thread_count++;
+					} while (Thread32Next(hSnapshot, &te32));
+				}
+				CloseHandle(hSnapshot);
+			}
+		}
+	}
+#endif
 }
 
 /*
@@ -83,6 +168,26 @@ pg_rusage_show(const PGRUsage *ru0)
 					   (long) (r.ru_oublock - ru0->ru.ru_oublock));
 	appendStringInfo(&str, _("!\t%ld/%ld [%ld/%ld] voluntary/involuntary context switches\n"),
 					 r.ru_nvcsw - ru0->ru.ru_nvcsw, r.ru_nivcsw - ru0->ru.ru_nivcsw,
 					 r.ru_nvcsw, r.ru_nivcsw);
+
+#ifdef WIN32
+	/* Show Windows-specific extended statistics */
+	appendStringInfo(&str, _("!\tWindows: %zu KB working set (%zu KB peak), %zu KB private\n"),
+					 r_win32.working_set_size / 1024,
+					 r_win32.peak_working_set_size / 1024,
+					 r_win32.private_bytes / 1024);
+	
+	appendStringInfo(&str, _("!\tI/O: %llu bytes read (%u ops), %llu write (%u ops), %llu other\n"),
+					 (unsigned long long)(r_win32.io_read_bytes - ru0->win32.io_read_bytes),
+					 r_win32.io_read_ops - ru0->win32.io_read_ops,
+					 (unsigned long long)(r_win32.io_write_bytes - ru0->win32.io_write_bytes),
+					 r_win32.io_write_ops - ru0->win32.io_write_ops,
+					 (unsigned long long)(r_win32.io_other_bytes - ru0->win32.io_other_bytes));
+	
+	appendStringInfo(&str, _("!\tResources: %u handles, %u threads, %u page faults\n"),
+					 r_win32.handle_count,
+					 r_win32.thread_count,
+					 r_win32.page_fault_count - ru0->win32.page_fault_count);
+#endif
 
 	return str.data;
 }
diff --git a/src/backend/utils/misc/Makefile b/src/backend/utils/misc/Makefile
index 3456789..cdefghi 100644
--- a/src/backend/utils/misc/Makefile
+++ b/src/backend/utils/misc/Makefile
@@ -8,3 +8,7 @@ include $(top_builddir)/src/Makefile.global
 OBJS = \
 	guc.o \
 	pg_rusage.o
+
+ifeq ($(PORTNAME), win32)
+LIBS += -lpsapi
+endif