Index: src/backend/utils/adt/pg_locale.c
===================================================================
--- src/backend/utils/adt/pg_locale.c	(HEAD)
+++ src/backend/utils/adt/pg_locale.c	(pg_locale-1125)
@@ -51,6 +51,7 @@
 #include <time.h>
 
 #include "catalog/pg_control.h"
+#include "mb/pg_wchar.h"
 #include "utils/memutils.h"
 #include "utils/pg_locale.h"
 
@@ -452,7 +453,54 @@
 	return &CurrentLocaleConv;
 }
 
+#ifdef WIN32
+/*
+ * On win32, strftime() returns the encoding in CP_ACP, which is likely
+ * different from SERVER_ENCODING. This is especially important in Japanese
+ * versions of Windows which will use SJIS encoding, which we don't support
+ * as a server encoding.
+ *
+ * Replace strftime() with a version that gets the string in UTF16 and then
+ * converts it to the appropriate encoding as necessary.
+ */
+static size_t
+strftime_win32(char *dst, size_t dstlen, const wchar_t *format, const struct tm *tm)
+{
+	size_t	len;
+	wchar_t	wbuf[MAX_L10N_DATA];
+	int		encoding;
 
+	encoding = GetDatabaseEncoding();
+
+	len = wcsftime(wbuf, sizeof(wbuf), format, tm);
+	if (len == 0)
+		/* strftime call failed - return 0 with the contents of dst unspecified */
+		return 0;
+
+	len = WideCharToMultiByte(CP_UTF8, 0, wbuf, len, dst, dstlen, NULL, NULL);
+	if (len == 0)
+		elog(ERROR,
+			"could not convert string to UTF-8:error %lu", GetLastError());
+
+	dst[len] = '\0';
+	if (encoding != PG_UTF8)
+	{
+		char *convstr = pg_do_encoding_conversion(dst, len, PG_UTF8, encoding);
+		if (dst != convstr)
+		{
+			StrNCpy(dst, convstr, dstlen);
+			len = strlen(dst);
+		}
+	}
+
+	return len;
+}
+
+#define strftime(a,b,c,d) strftime_win32(a,b,L##c,d)
+
+#endif /* WIN32 */
+
+
 /*
  * Update the lc_time localization cache variables if needed.
  */