0001-Allow-ICU-to-use-SortSupport-on-Windows-with-UTF-8.patch

From fca07aca51fb7979f19180712707233ff0e6f4b4 Mon Sep 17 00:00:00 2001
From: Peter Geoghegan <pg@bowt.ie>
Date: Sat, 16 Sep 2017 13:36:25 -0700
Subject: [PATCH] Allow ICU to use SortSupport on Windows with UTF-8.

There is no reason to ever prevent the use of SortSupport on Windows
when ICU locales are used.  We previously avoided SortSupport on Windows
with UTF-8 server encoding and a non C-locale due to restrictions in
Windows' libc functionality.

This is now considered to be a restriction in one platform's libc
collation provider, and not a more general platform restriction.
---
 src/backend/utils/adt/varlena.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index ebfb823..ad8ebed 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -1828,7 +1828,8 @@ varstr_sortsupport(SortSupport ssup, Oid collid, bool bpchar)
 	 * UTF-8 and we are not using the C collation, complex hacks are required.
 	 * We don't currently have a comparator that handles that case, so we fall
 	 * back on the slow method of having the sort code invoke bttextcmp() (in
-	 * the case of text) via the fmgr trampoline.
+	 * the case of text) via the fmgr trampoline.  (ICU locales work just the
+	 * same on Windows, however.)
 	 */
 	if (lc_collate_is_c(collid))
 	{
@@ -1840,7 +1841,8 @@ varstr_sortsupport(SortSupport ssup, Oid collid, bool bpchar)
 		collate_c = true;
 	}
 #ifdef WIN32
-	else if (GetDatabaseEncoding() == PG_UTF8)
+	else if (GetDatabaseEncoding() == PG_UTF8 &&
+			 !(locale && locale->provider == COLLPROVIDER_ICU))
 		return;
 #endif
 	else
-- 
2.7.4