WIN32 pg_import_system_collations

From ddf3114e82dc32edb59278d9ed2cb995222a5adf Mon Sep 17 00:00:00 2001
From: Juan Jose Santamaria Flecha <juanjo.santamaria@gmail.com>
Date: Fri, 10 Dec 2021 17:44:15 -0500
Subject: [PATCH] WIN32 pg_import_system_collations . Adds the
 pg_import_system_collations() functionality for Windows newer than 2008 using
 EnumSystemLocalesEx(). Also adding a test emulating collate.linux.utf8 but
 for Windows-1252

---
 src/backend/commands/collationcmds.c               |  197 +++-
 .../regress/expected/collate.windows.win1252.out   | 1019 ++++++++++++++++++++
 .../regress/expected/collate.windows.win1252_1.out |   12 +
 src/test/regress/parallel_schedule                 |    2 +-
 src/test/regress/sql/collate.windows.win1252.sql   |  418 ++++++++
 src/tools/msvc/vcregress.pl                        |    3 +-
 6 files changed, 1599 insertions(+), 52 deletions(-)
 create mode 100644 src/test/regress/expected/collate.windows.win1252.out
 create mode 100644 src/test/regress/expected/collate.windows.win1252_1.out
 create mode 100644 src/test/regress/sql/collate.windows.win1252.sql

diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 53fc579..c286113 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -522,6 +522,128 @@ get_icu_locale_comment(const char *localename)
 }
 #endif							/* USE_ICU */
 
+/* will we use EnumSystemLocalesEx in pg_import_system_collations? */
+#if defined(WIN32) && _WIN32_WINNT >= 0x0600
+#define ENUM_SYSTEM_LOCALE
+#endif
+
+#if defined(READ_LOCALE_A_OUTPUT) || defined(ENUM_SYSTEM_LOCALE)
+/*
+ * Create a collation if the input locale is valid for so.
+ * Also keeps track of the number of valid locales and collations created.
+ */
+static int
+CollationFromLocale(char *localebuf, int *nvalid, int *ncreated, int nspid)
+{
+	int			enc;
+	Oid			collid;
+
+	/*
+	 * Some systems have locale names that don't consist entirely of
+	 * ASCII letters (such as "bokm&aring;l" or "fran&ccedil;ais").
+	 * This is pretty silly, since we need the locale itself to
+	 * interpret the non-ASCII characters. We can't do much with
+	 * those, so we filter them out.
+	 */
+	if (!pg_is_ascii(localebuf))
+	{
+		elog(DEBUG1, "skipping locale with non-ASCII name: \"%s\"", localebuf);
+		return -1;
+	}
+
+	enc = pg_get_encoding_from_locale(localebuf, false);
+	if (enc < 0)
+	{
+		elog(DEBUG1, "skipping locale with unrecognized encoding: \"%s\"",
+			 localebuf);
+		return -1;
+	}
+	if (!PG_VALID_BE_ENCODING(enc))
+	{
+		elog(DEBUG1, "skipping locale with client-only encoding: \"%s\"", localebuf);
+		return -1;
+	}
+	if (enc == PG_SQL_ASCII)
+		return -1;		/* C/POSIX are already in the catalog */
+
+	/* count valid locales found in operating system */
+	*nvalid += 1;
+
+	/*
+	 * Create a collation named the same as the locale, but quietly
+	 * doing nothing if it already exists.  This is the behavior we
+	 * need even at initdb time, because some versions of "locale -a"
+	 * can report the same locale name more than once.  And it's
+	 * convenient for later import runs, too, since you just about
+	 * always want to add on new locales without a lot of chatter
+	 * about existing ones.
+	 */
+	collid = CollationCreate(localebuf, nspid, GetUserId(),
+							 COLLPROVIDER_LIBC, true, enc,
+							 localebuf, localebuf,
+							 get_collation_actual_version(COLLPROVIDER_LIBC, localebuf),
+							 true, true);
+	if (OidIsValid(collid))
+	{
+		*ncreated += 1;
+
+		/* Must do CCI between inserts to handle duplicates correctly */
+		CommandCounterIncrement();
+	}
+
+	return enc;
+}
+#endif							/* defined(READ_LOCALE_A_OUTPUT) || defined(ENUM_SYSTEM_LOCALE) */
+
+#ifdef ENUM_SYSTEM_LOCALE
+/* Parameter to be passed to the callback function win32_read_locale() */
+typedef struct
+{
+	int		   *ncreated;
+	int		   *nvalid;
+	Oid			nspid;
+} CollParam;
+
+/*
+ * Callback function for EnumSystemLocalesEx() in pg_import_system_collations()
+ * Creates a collation for every valid locale.
+ */
+BOOL CALLBACK
+win32_read_locale(LPWSTR pStr, DWORD dwFlags, LPARAM lparam)
+{
+	CollParam  *param = (CollParam *) lparam;
+	char		localebuf[NAMEDATALEN];
+	int			result;
+	char	   *hyphen;
+
+	(void) dwFlags;
+
+	result = WideCharToMultiByte(CP_ACP, 0, pStr, -1, localebuf, NAMEDATALEN,
+								 NULL, NULL);
+
+	if (result == 0)
+	{
+		if (GetLastError() == ERROR_INSUFFICIENT_BUFFER)
+			elog(DEBUG1, "skipping locale with too-long name: \"%s\"", localebuf);
+		return (TRUE);
+	}
+	if (localebuf[0] == '\0')
+		return (TRUE);
+
+	/*
+	 * Windows will use hyphens between language and territory, where ANSI
+	 * uses an underscore. Simply make it ANSI looking.
+	 */
+	hyphen = strchr(localebuf, '-');
+	if (hyphen)
+		*hyphen = '_';
+
+	CollationFromLocale(localebuf, param->nvalid, param->ncreated, param->nspid);
+
+	return (TRUE);
+}
+#endif							/* ENUM_SYSTEM_LOCALE */
+
 
 /*
  * pg_import_system_collations: add known system collations to pg_collation
@@ -581,58 +703,9 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 			}
 			localebuf[len - 1] = '\0';
 
-			/*
-			 * Some systems have locale names that don't consist entirely of
-			 * ASCII letters (such as "bokm&aring;l" or "fran&ccedil;ais").
-			 * This is pretty silly, since we need the locale itself to
-			 * interpret the non-ASCII characters. We can't do much with
-			 * those, so we filter them out.
-			 */
-			if (!pg_is_ascii(localebuf))
-			{
-				elog(DEBUG1, "skipping locale with non-ASCII name: \"%s\"", localebuf);
-				continue;
-			}
-
-			enc = pg_get_encoding_from_locale(localebuf, false);
+			enc = CollationFromLocale(localebuf, &nvalid, &ncreated, nspid);
 			if (enc < 0)
-			{
-				elog(DEBUG1, "skipping locale with unrecognized encoding: \"%s\"",
-					 localebuf);
-				continue;
-			}
-			if (!PG_VALID_BE_ENCODING(enc))
-			{
-				elog(DEBUG1, "skipping locale with client-only encoding: \"%s\"", localebuf);
 				continue;
-			}
-			if (enc == PG_SQL_ASCII)
-				continue;		/* C/POSIX are already in the catalog */
-
-			/* count valid locales found in operating system */
-			nvalid++;
-
-			/*
-			 * Create a collation named the same as the locale, but quietly
-			 * doing nothing if it already exists.  This is the behavior we
-			 * need even at initdb time, because some versions of "locale -a"
-			 * can report the same locale name more than once.  And it's
-			 * convenient for later import runs, too, since you just about
-			 * always want to add on new locales without a lot of chatter
-			 * about existing ones.
-			 */
-			collid = CollationCreate(localebuf, nspid, GetUserId(),
-									 COLLPROVIDER_LIBC, true, enc,
-									 localebuf, localebuf,
-									 get_collation_actual_version(COLLPROVIDER_LIBC, localebuf),
-									 true, true);
-			if (OidIsValid(collid))
-			{
-				ncreated++;
-
-				/* Must do CCI between inserts to handle duplicates correctly */
-				CommandCounterIncrement();
-			}
 
 			/*
 			 * Generate aliases such as "en_US" in addition to "en_US.utf8"
@@ -702,6 +775,30 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 	}
 #endif							/* READ_LOCALE_A_OUTPUT */
 
+	/* Load collations known to WIN32 */
+#ifdef ENUM_SYSTEM_LOCALE
+	{
+		int			nvalid = 0;
+		CollParam	param;
+		param.ncreated = &ncreated;
+		param.nvalid = &nvalid;
+		param.nspid = nspid;
+
+		/*
+		 * Enumerate the locales that are either installed on or supported
+		 * by the OS.
+		 */
+		if (!EnumSystemLocalesEx(win32_read_locale, LOCALE_ALL,
+								 (LPARAM) &param, NULL))
+			_dosmaperr(GetLastError());
+
+		/* Give a warning if EnumSystemLocalesEx seems to be malfunctioning */
+		if (nvalid == 0)
+			ereport(WARNING,
+					(errmsg("no usable system locales were found")));
+	}
+#endif							/* ENUM_SYSTEM_LOCALE */
+
 	/*
 	 * Load collations known to ICU
 	 *
diff --git a/src/test/regress/expected/collate.windows.win1252.out b/src/test/regress/expected/collate.windows.win1252.out
new file mode 100644
index 0000000..cc91c85
--- /dev/null
+++ b/src/test/regress/expected/collate.windows.win1252.out
@@ -0,0 +1,1019 @@
+/*
+ * This test is for Windows/Visual Studio systems and assumes that a full set
+ * of locales is installed. It must be run in a database with WIN1252 encoding,
+ * because of the locales' encondings. We lose some interesting cases from the
+ * UTF-8 version, like Turkish dotted and undotted 'i' or Greek sigma.
+ */
+SELECT getdatabaseencoding() <> 'WIN1252' OR
+       (SELECT count(*) FROM pg_collation WHERE collname IN ('de_DE', 'en_US', 'sv_SE') AND collencoding = pg_char_to_encoding('WIN1252')) <> 3 OR
+       version() !~ 'Visual C\+\+'
+       AS skip_test \gset
+\if :skip_test
+\quit
+\endif
+SET client_encoding TO WIN1252;
+CREATE SCHEMA collate_tests;
+SET search_path = collate_tests;
+CREATE TABLE collate_test1 (
+    a int,
+    b text COLLATE "en_US" NOT NULL
+);
+\d collate_test1
+        Table "collate_tests.collate_test1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | text    | en_US     | not null | 
+
+CREATE TABLE collate_test_fail (
+    a int,
+    b text COLLATE "ja_JP.eucjp"
+);
+ERROR:  collation "ja_JP.eucjp" for encoding "WIN1252" does not exist
+LINE 3:     b text COLLATE "ja_JP.eucjp"
+                   ^
+CREATE TABLE collate_test_fail (
+    a int,
+    b text COLLATE "foo"
+);
+ERROR:  collation "foo" for encoding "WIN1252" does not exist
+LINE 3:     b text COLLATE "foo"
+                   ^
+CREATE TABLE collate_test_fail (
+    a int COLLATE "en_US",
+    b text
+);
+ERROR:  collations are not supported by type integer
+LINE 2:     a int COLLATE "en_US",
+                  ^
+CREATE TABLE collate_test_like (
+    LIKE collate_test1
+);
+\d collate_test_like
+      Table "collate_tests.collate_test_like"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | text    | en_US     | not null | 
+
+CREATE TABLE collate_test2 (
+    a int,
+    b text COLLATE "sv_SE"
+);
+CREATE TABLE collate_test3 (
+    a int,
+    b text COLLATE "C"
+);
+INSERT INTO collate_test1 VALUES (1, 'abc'), (2, '�bc'), (3, 'bbc'), (4, 'ABC');
+INSERT INTO collate_test2 SELECT * FROM collate_test1;
+INSERT INTO collate_test3 SELECT * FROM collate_test1;
+SELECT * FROM collate_test1 WHERE b >= 'bbc';
+ a |  b  
+---+-----
+ 3 | bbc
+(1 row)
+
+SELECT * FROM collate_test2 WHERE b >= 'bbc';
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test3 WHERE b >= 'bbc';
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test3 WHERE b >= 'BBC';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+(3 rows)
+
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc';
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b >= 'bbc' COLLATE "C";
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "C";
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "en_US";
+ERROR:  collation mismatch between explicit collations "C" and "en_US"
+LINE 1: ...* FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "e...
+                                                             ^
+CREATE DOMAIN testdomain_sv AS text COLLATE "sv_SE";
+CREATE DOMAIN testdomain_i AS int COLLATE "sv_SE"; -- fails
+ERROR:  collations are not supported by type integer
+CREATE TABLE collate_test4 (
+    a int,
+    b testdomain_sv
+);
+INSERT INTO collate_test4 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test4 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+CREATE TABLE collate_test5 (
+    a int,
+    b testdomain_sv COLLATE "en_US"
+);
+INSERT INTO collate_test5 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test5 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, b FROM collate_test1 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, b FROM collate_test2 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b FROM collate_test3 ORDER BY b;
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+-- star expansion
+SELECT * FROM collate_test1 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT * FROM collate_test2 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT * FROM collate_test3 ORDER BY b;
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+-- constant expression folding
+SELECT 'bbc' COLLATE "en_US" > '�bc' COLLATE "en_US" AS "true";
+ true 
+------
+ t
+(1 row)
+
+SELECT 'bbc' COLLATE "sv_SE" > '�bc' COLLATE "sv_SE" AS "false";
+ false 
+-------
+ f
+(1 row)
+
+-- LIKE/ILIKE
+SELECT * FROM collate_test1 WHERE b LIKE 'abc';
+ a |  b  
+---+-----
+ 1 | abc
+(1 row)
+
+SELECT * FROM collate_test1 WHERE b LIKE 'abc%';
+ a |  b  
+---+-----
+ 1 | abc
+(1 row)
+
+SELECT * FROM collate_test1 WHERE b LIKE '%bc%';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+(3 rows)
+
+SELECT * FROM collate_test1 WHERE b ILIKE 'abc';
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b ILIKE 'abc%';
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b ILIKE '%bc%';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+ 4 | ABC
+(4 rows)
+
+-- The following actually exercises the selectivity estimation for ILIKE.
+SELECT relname FROM pg_class WHERE relname ILIKE 'abc%';
+ relname 
+---------
+(0 rows)
+
+-- regular expressions
+SELECT * FROM collate_test1 WHERE b ~ '^abc$';
+ a |  b  
+---+-----
+ 1 | abc
+(1 row)
+
+SELECT * FROM collate_test1 WHERE b ~ '^abc';
+ a |  b  
+---+-----
+ 1 | abc
+(1 row)
+
+SELECT * FROM collate_test1 WHERE b ~ 'bc';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+(3 rows)
+
+SELECT * FROM collate_test1 WHERE b ~* '^abc$';
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b ~* '^abc';
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b ~* 'bc';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+ 4 | ABC
+(4 rows)
+
+CREATE TABLE collate_test6 (
+    a int,
+    b text COLLATE "en_US"
+);
+INSERT INTO collate_test6 VALUES (1, 'abc'), (2, 'ABC'), (3, '123'), (4, 'ab1'),
+                                 (5, 'a1!'), (6, 'a c'), (7, '!.;'), (8, '   '),
+                                 (9, '�b�'), (10, '�B�');
+SELECT b,
+       b ~ '^[[:alpha:]]+$' AS is_alpha,
+       b ~ '^[[:upper:]]+$' AS is_upper,
+       b ~ '^[[:lower:]]+$' AS is_lower,
+       b ~ '^[[:digit:]]+$' AS is_digit,
+       b ~ '^[[:alnum:]]+$' AS is_alnum,
+       b ~ '^[[:graph:]]+$' AS is_graph,
+       b ~ '^[[:print:]]+$' AS is_print,
+       b ~ '^[[:punct:]]+$' AS is_punct,
+       b ~ '^[[:space:]]+$' AS is_space
+FROM collate_test6;
+  b  | is_alpha | is_upper | is_lower | is_digit | is_alnum | is_graph | is_print | is_punct | is_space 
+-----+----------+----------+----------+----------+----------+----------+----------+----------+----------
+ abc | t        | f        | t        | f        | t        | t        | t        | f        | f
+ ABC | t        | t        | f        | f        | t        | t        | t        | f        | f
+ 123 | f        | f        | f        | t        | t        | t        | t        | f        | f
+ ab1 | f        | f        | f        | f        | t        | t        | t        | f        | f
+ a1! | f        | f        | f        | f        | f        | t        | t        | f        | f
+ a c | f        | f        | f        | f        | f        | f        | t        | f        | f
+ !.; | f        | f        | f        | f        | f        | t        | t        | t        | f
+     | f        | f        | f        | f        | f        | f        | t        | f        | t
+ �b� | t        | f        | t        | f        | t        | t        | t        | f        | f
+ �B� | t        | t        | f        | f        | t        | t        | t        | f        | f
+(10 rows)
+
+-- The following actually exercises the selectivity estimation for ~*.
+SELECT relname FROM pg_class WHERE relname ~* '^abc';
+ relname 
+---------
+(0 rows)
+
+-- to_char
+SET lc_time TO 'de_DE';
+SELECT to_char(date '2010-03-01', 'DD TMMON YYYY');
+   to_char   
+-------------
+ 01 MRZ 2010
+(1 row)
+
+SELECT to_char(date '2010-03-01', 'DD TMMON YYYY' COLLATE "de_DE");
+   to_char   
+-------------
+ 01 MRZ 2010
+(1 row)
+
+-- to_date
+SELECT to_date('01 M�R 2010', 'DD TMMON YYYY');
+ERROR:  invalid value "M�R" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_date('01 M�r 2010', 'DD TMMON YYYY');
+ERROR:  invalid value "M�r" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_date('1234567890ab 2010', 'TMMONTH YYYY'); -- fail
+ERROR:  invalid value "1234567890ab" for "MONTH"
+DETAIL:  The given value did not match any of the allowed values for this field.
+-- backwards parsing
+CREATE VIEW collview1 AS SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc';
+CREATE VIEW collview2 AS SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+SELECT table_name, view_definition FROM information_schema.views
+  WHERE table_name LIKE 'collview%' ORDER BY 1;
+ table_name |                     view_definition                     
+------------+---------------------------------------------------------
+ collview1  |  SELECT collate_test1.a,                               +
+            |     collate_test1.b                                    +
+            |    FROM collate_test1                                  +
+            |   WHERE ((collate_test1.b COLLATE "C") >= 'bbc'::text);
+ collview2  |  SELECT collate_test1.a,                               +
+            |     collate_test1.b                                    +
+            |    FROM collate_test1                                  +
+            |   ORDER BY (collate_test1.b COLLATE "C");
+(2 rows)
+
+-- collation propagation in various expression types
+SELECT a, coalesce(b, 'foo') FROM collate_test1 ORDER BY 2;
+ a | coalesce 
+---+----------
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, coalesce(b, 'foo') FROM collate_test2 ORDER BY 2;
+ a | coalesce 
+---+----------
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, coalesce(b, 'foo') FROM collate_test3 ORDER BY 2;
+ a | coalesce 
+---+----------
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b, greatest(b, 'CCC') FROM collate_test1 ORDER BY 3;
+ a |  b  | greatest 
+---+-----+----------
+ 1 | abc | CCC
+ 2 | �bc | CCC
+ 3 | bbc | CCC
+ 4 | ABC | CCC
+(4 rows)
+
+SELECT a, b, greatest(b, 'CCC') FROM collate_test2 ORDER BY 3;
+ a |  b  | greatest 
+---+-----+----------
+ 1 | abc | CCC
+ 3 | bbc | CCC
+ 4 | ABC | CCC
+ 2 | �bc | �bc
+(4 rows)
+
+SELECT a, b, greatest(b, 'CCC') FROM collate_test3 ORDER BY 3;
+ a |  b  | greatest 
+---+-----+----------
+ 4 | ABC | CCC
+ 1 | abc | abc
+ 3 | bbc | bbc
+ 2 | �bc | �bc
+(4 rows)
+
+SELECT a, nullif(b, 'abc') FROM collate_test1 ORDER BY 2;
+ a | nullif 
+---+--------
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+ 1 | 
+(4 rows)
+
+SELECT a, nullif(b, 'abc') FROM collate_test2 ORDER BY 2;
+ a | nullif 
+---+--------
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+ 1 | 
+(4 rows)
+
+SELECT a, nullif(b, 'abc') FROM collate_test3 ORDER BY 2;
+ a | nullif 
+---+--------
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+ 1 | 
+(4 rows)
+
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test1 ORDER BY 2;
+ a |  b   
+---+------
+ 4 | ABC
+ 2 | �bc
+ 1 | abcd
+ 3 | bbc
+(4 rows)
+
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test2 ORDER BY 2;
+ a |  b   
+---+------
+ 4 | ABC
+ 1 | abcd
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test3 ORDER BY 2;
+ a |  b   
+---+------
+ 4 | ABC
+ 1 | abcd
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+CREATE DOMAIN testdomain AS text;
+SELECT a, b::testdomain FROM collate_test1 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, b::testdomain FROM collate_test2 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b::testdomain FROM collate_test3 ORDER BY 2;
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b::testdomain_sv FROM collate_test3 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT min(b), max(b) FROM collate_test1;
+ min | max 
+-----+-----
+ abc | bbc
+(1 row)
+
+SELECT min(b), max(b) FROM collate_test2;
+ min | max 
+-----+-----
+ abc | �bc
+(1 row)
+
+SELECT min(b), max(b) FROM collate_test3;
+ min | max 
+-----+-----
+ ABC | �bc
+(1 row)
+
+SELECT array_agg(b ORDER BY b) FROM collate_test1;
+     array_agg     
+-------------------
+ {abc,ABC,�bc,bbc}
+(1 row)
+
+SELECT array_agg(b ORDER BY b) FROM collate_test2;
+     array_agg     
+-------------------
+ {abc,ABC,bbc,�bc}
+(1 row)
+
+SELECT array_agg(b ORDER BY b) FROM collate_test3;
+     array_agg     
+-------------------
+ {ABC,abc,bbc,�bc}
+(1 row)
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test1 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 1 | abc
+ 4 | ABC
+ 4 | ABC
+ 2 | �bc
+ 2 | �bc
+ 3 | bbc
+ 3 | bbc
+(8 rows)
+
+SELECT a, b FROM collate_test2 UNION SELECT a, b FROM collate_test2 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b FROM collate_test3 WHERE a < 4 INTERSECT SELECT a, b FROM collate_test3 WHERE a > 1 ORDER BY 2;
+ a |  b  
+---+-----
+ 3 | bbc
+ 2 | �bc
+(2 rows)
+
+SELECT a, b FROM collate_test3 EXCEPT SELECT a, b FROM collate_test3 WHERE a < 2 ORDER BY 2;
+ a |  b  
+---+-----
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(3 rows)
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+ERROR:  could not determine which collation to use for string comparison
+HINT:  Use the COLLATE clause to set the collation explicitly.
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3; -- ok
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+ 4 | ABC
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+ 4 | ABC
+(8 rows)
+
+SELECT a, b FROM collate_test1 UNION SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+ERROR:  collation mismatch between implicit collations "en_US" and "C"
+LINE 1: SELECT a, b FROM collate_test1 UNION SELECT a, b FROM collat...
+                                                       ^
+HINT:  You can choose the collation by applying the COLLATE clause to one or both expressions.
+SELECT a, b COLLATE "C" FROM collate_test1 UNION SELECT a, b FROM collate_test3 ORDER BY 2; -- ok
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b FROM collate_test1 INTERSECT SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+ERROR:  collation mismatch between implicit collations "en_US" and "C"
+LINE 1: ...ELECT a, b FROM collate_test1 INTERSECT SELECT a, b FROM col...
+                                                             ^
+HINT:  You can choose the collation by applying the COLLATE clause to one or both expressions.
+SELECT a, b FROM collate_test1 EXCEPT SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+ERROR:  collation mismatch between implicit collations "en_US" and "C"
+LINE 1: SELECT a, b FROM collate_test1 EXCEPT SELECT a, b FROM colla...
+                                                        ^
+HINT:  You can choose the collation by applying the COLLATE clause to one or both expressions.
+CREATE TABLE test_u AS SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3; -- fail
+ERROR:  no collation was derived for column "b" with collatable type text
+HINT:  Use the COLLATE clause to set the collation explicitly.
+-- collation mismatch between recursive and non-recursive term
+WITH RECURSIVE foo(x) AS
+   (SELECT x FROM (VALUES('a' COLLATE "en_US"),('b')) t(x)
+   UNION ALL
+   SELECT (x || 'c') COLLATE "de_DE" FROM foo WHERE length(x) < 10)
+SELECT * FROM foo;
+ERROR:  recursive query "foo" column 1 has collation "en_US" in non-recursive term but collation "de_DE" overall
+LINE 2:    (SELECT x FROM (VALUES('a' COLLATE "en_US"),('b')) t(x)
+                   ^
+HINT:  Use the COLLATE clause to set the collation of the non-recursive term.
+-- casting
+SELECT CAST('42' AS text COLLATE "C");
+ERROR:  syntax error at or near "COLLATE"
+LINE 1: SELECT CAST('42' AS text COLLATE "C");
+                                 ^
+SELECT a, CAST(b AS varchar) FROM collate_test1 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, CAST(b AS varchar) FROM collate_test2 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, CAST(b AS varchar) FROM collate_test3 ORDER BY 2;
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+-- propagation of collation in SQL functions (inlined and non-inlined cases)
+-- and plpgsql functions too
+CREATE FUNCTION mylt (text, text) RETURNS boolean LANGUAGE sql
+    AS $$ select $1 < $2 $$;
+CREATE FUNCTION mylt_noninline (text, text) RETURNS boolean LANGUAGE sql
+    AS $$ select $1 < $2 limit 1 $$;
+CREATE FUNCTION mylt_plpgsql (text, text) RETURNS boolean LANGUAGE plpgsql
+    AS $$ begin return $1 < $2; end $$;
+SELECT a.b AS a, b.b AS b, a.b < b.b AS lt,
+       mylt(a.b, b.b), mylt_noninline(a.b, b.b), mylt_plpgsql(a.b, b.b)
+FROM collate_test1 a, collate_test1 b
+ORDER BY a.b, b.b;
+  a  |  b  | lt | mylt | mylt_noninline | mylt_plpgsql 
+-----+-----+----+------+----------------+--------------
+ abc | abc | f  | f    | f              | f
+ abc | ABC | t  | t    | t              | t
+ abc | �bc | t  | t    | t              | t
+ abc | bbc | t  | t    | t              | t
+ ABC | abc | f  | f    | f              | f
+ ABC | ABC | f  | f    | f              | f
+ ABC | �bc | t  | t    | t              | t
+ ABC | bbc | t  | t    | t              | t
+ �bc | abc | f  | f    | f              | f
+ �bc | ABC | f  | f    | f              | f
+ �bc | �bc | f  | f    | f              | f
+ �bc | bbc | t  | t    | t              | t
+ bbc | abc | f  | f    | f              | f
+ bbc | ABC | f  | f    | f              | f
+ bbc | �bc | f  | f    | f              | f
+ bbc | bbc | f  | f    | f              | f
+(16 rows)
+
+SELECT a.b AS a, b.b AS b, a.b < b.b COLLATE "C" AS lt,
+       mylt(a.b, b.b COLLATE "C"), mylt_noninline(a.b, b.b COLLATE "C"),
+       mylt_plpgsql(a.b, b.b COLLATE "C")
+FROM collate_test1 a, collate_test1 b
+ORDER BY a.b, b.b;
+  a  |  b  | lt | mylt | mylt_noninline | mylt_plpgsql 
+-----+-----+----+------+----------------+--------------
+ abc | abc | f  | f    | f              | f
+ abc | ABC | f  | f    | f              | f
+ abc | �bc | t  | t    | t              | t
+ abc | bbc | t  | t    | t              | t
+ ABC | abc | t  | t    | t              | t
+ ABC | ABC | f  | f    | f              | f
+ ABC | �bc | t  | t    | t              | t
+ ABC | bbc | t  | t    | t              | t
+ �bc | abc | f  | f    | f              | f
+ �bc | ABC | f  | f    | f              | f
+ �bc | �bc | f  | f    | f              | f
+ �bc | bbc | f  | f    | f              | f
+ bbc | abc | f  | f    | f              | f
+ bbc | ABC | f  | f    | f              | f
+ bbc | �bc | t  | t    | t              | t
+ bbc | bbc | f  | f    | f              | f
+(16 rows)
+
+-- collation override in plpgsql
+CREATE FUNCTION mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+  xx text := x;
+  yy text := y;
+begin
+  return xx < yy;
+end
+$$;
+SELECT mylt2('a', 'B' collate "en_US") as t, mylt2('a', 'B' collate "C") as f;
+ t | f 
+---+---
+ t | f
+(1 row)
+
+CREATE OR REPLACE FUNCTION
+  mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+  xx text COLLATE "POSIX" := x;
+  yy text := y;
+begin
+  return xx < yy;
+end
+$$;
+SELECT mylt2('a', 'B') as f;
+ f 
+---
+ f
+(1 row)
+
+SELECT mylt2('a', 'B' collate "C") as fail; -- conflicting collations
+ERROR:  could not determine which collation to use for string comparison
+HINT:  Use the COLLATE clause to set the collation explicitly.
+CONTEXT:  PL/pgSQL function mylt2(text,text) line 6 at RETURN
+SELECT mylt2('a', 'B' collate "POSIX") as f;
+ f 
+---
+ f
+(1 row)
+
+-- polymorphism
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test1)) ORDER BY 1;
+ unnest 
+--------
+ abc
+ ABC
+ �bc
+ bbc
+(4 rows)
+
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test2)) ORDER BY 1;
+ unnest 
+--------
+ abc
+ ABC
+ bbc
+ �bc
+(4 rows)
+
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test3)) ORDER BY 1;
+ unnest 
+--------
+ ABC
+ abc
+ bbc
+ �bc
+(4 rows)
+
+CREATE FUNCTION dup (anyelement) RETURNS anyelement
+    AS 'select $1' LANGUAGE sql;
+SELECT a, dup(b) FROM collate_test1 ORDER BY 2;
+ a | dup 
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, dup(b) FROM collate_test2 ORDER BY 2;
+ a | dup 
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, dup(b) FROM collate_test3 ORDER BY 2;
+ a | dup 
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+-- indexes
+CREATE INDEX collate_test1_idx1 ON collate_test1 (b);
+CREATE INDEX collate_test1_idx2 ON collate_test1 (b COLLATE "C");
+CREATE INDEX collate_test1_idx3 ON collate_test1 ((b COLLATE "C")); -- this is different grammatically
+CREATE INDEX collate_test1_idx4 ON collate_test1 (((b||'foo') COLLATE "POSIX"));
+CREATE INDEX collate_test1_idx5 ON collate_test1 (a COLLATE "C"); -- fail
+ERROR:  collations are not supported by type integer
+CREATE INDEX collate_test1_idx6 ON collate_test1 ((a COLLATE "C")); -- fail
+ERROR:  collations are not supported by type integer
+LINE 1: ...ATE INDEX collate_test1_idx6 ON collate_test1 ((a COLLATE "C...
+                                                             ^
+SELECT relname, pg_get_indexdef(oid) FROM pg_class WHERE relname LIKE 'collate_test%_idx%' ORDER BY 1;
+      relname       |                                                  pg_get_indexdef                                                  
+--------------------+-------------------------------------------------------------------------------------------------------------------
+ collate_test1_idx1 | CREATE INDEX collate_test1_idx1 ON collate_tests.collate_test1 USING btree (b)
+ collate_test1_idx2 | CREATE INDEX collate_test1_idx2 ON collate_tests.collate_test1 USING btree (b COLLATE "C")
+ collate_test1_idx3 | CREATE INDEX collate_test1_idx3 ON collate_tests.collate_test1 USING btree (b COLLATE "C")
+ collate_test1_idx4 | CREATE INDEX collate_test1_idx4 ON collate_tests.collate_test1 USING btree (((b || 'foo'::text)) COLLATE "POSIX")
+(4 rows)
+
+-- schema manipulation commands
+CREATE ROLE regress_test_role;
+CREATE SCHEMA test_schema;
+-- We need to do this this way to cope with varying names for encodings:
+do $$
+BEGIN
+  EXECUTE 'CREATE COLLATION test0 (locale = ' ||
+          quote_literal(current_setting('lc_collate')) || ');';
+END
+$$;
+CREATE COLLATION test0 FROM "C"; -- fail, duplicate name
+ERROR:  collation "test0" already exists
+CREATE COLLATION IF NOT EXISTS test0 FROM "C"; -- ok, skipped
+NOTICE:  collation "test0" already exists, skipping
+CREATE COLLATION IF NOT EXISTS test0 (locale = 'foo'); -- ok, skipped
+NOTICE:  collation "test0" for encoding "WIN1252" already exists, skipping
+do $$
+BEGIN
+  EXECUTE 'CREATE COLLATION test1 (lc_collate = ' ||
+          quote_literal(current_setting('lc_collate')) ||
+          ', lc_ctype = ' ||
+          quote_literal(current_setting('lc_ctype')) || ');';
+END
+$$;
+CREATE COLLATION test3 (lc_collate = 'en_US.utf8'); -- fail, need lc_ctype
+ERROR:  parameter "lc_ctype" must be specified
+CREATE COLLATION testx (locale = 'nonsense'); -- fail
+ERROR:  could not create locale "nonsense": No such file or directory
+DETAIL:  The operating system could not find any locale data for the locale name "nonsense".
+CREATE COLLATION test4 FROM nonsense;
+ERROR:  collation "nonsense" for encoding "WIN1252" does not exist
+CREATE COLLATION test5 FROM test0;
+SELECT collname FROM pg_collation WHERE collname LIKE 'test%' ORDER BY 1;
+ collname 
+----------
+ test0
+ test1
+ test5
+(3 rows)
+
+ALTER COLLATION test1 RENAME TO test11;
+ALTER COLLATION test0 RENAME TO test11; -- fail
+ERROR:  collation "test11" for encoding "WIN1252" already exists in schema "collate_tests"
+ALTER COLLATION test1 RENAME TO test22; -- fail
+ERROR:  collation "test1" for encoding "WIN1252" does not exist
+ALTER COLLATION test11 OWNER TO regress_test_role;
+ALTER COLLATION test11 OWNER TO nonsense;
+ERROR:  role "nonsense" does not exist
+ALTER COLLATION test11 SET SCHEMA test_schema;
+COMMENT ON COLLATION test0 IS 'US English';
+SELECT collname, nspname, obj_description(pg_collation.oid, 'pg_collation')
+    FROM pg_collation JOIN pg_namespace ON (collnamespace = pg_namespace.oid)
+    WHERE collname LIKE 'test%'
+    ORDER BY 1;
+ collname |    nspname    | obj_description 
+----------+---------------+-----------------
+ test0    | collate_tests | US English
+ test11   | test_schema   | 
+ test5    | collate_tests | 
+(3 rows)
+
+DROP COLLATION test0, test_schema.test11, test5;
+DROP COLLATION test0; -- fail
+ERROR:  collation "test0" for encoding "WIN1252" does not exist
+DROP COLLATION IF EXISTS test0;
+NOTICE:  collation "test0" does not exist, skipping
+SELECT collname FROM pg_collation WHERE collname LIKE 'test%';
+ collname 
+----------
+(0 rows)
+
+DROP SCHEMA test_schema;
+DROP ROLE regress_test_role;
+-- ALTER
+ALTER COLLATION "en_US" REFRESH VERSION;
+NOTICE:  version has not changed
+-- dependencies
+CREATE COLLATION test0 FROM "C";
+CREATE TABLE collate_dep_test1 (a int, b text COLLATE test0);
+CREATE DOMAIN collate_dep_dom1 AS text COLLATE test0;
+CREATE TYPE collate_dep_test2 AS (x int, y text COLLATE test0);
+CREATE VIEW collate_dep_test3 AS SELECT text 'foo' COLLATE test0 AS foo;
+CREATE TABLE collate_dep_test4t (a int, b text);
+CREATE INDEX collate_dep_test4i ON collate_dep_test4t (b COLLATE test0);
+DROP COLLATION test0 RESTRICT; -- fail
+ERROR:  cannot drop collation test0 because other objects depend on it
+DETAIL:  column b of table collate_dep_test1 depends on collation test0
+type collate_dep_dom1 depends on collation test0
+column y of composite type collate_dep_test2 depends on collation test0
+view collate_dep_test3 depends on collation test0
+index collate_dep_test4i depends on collation test0
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
+DROP COLLATION test0 CASCADE;
+NOTICE:  drop cascades to 5 other objects
+DETAIL:  drop cascades to column b of table collate_dep_test1
+drop cascades to type collate_dep_dom1
+drop cascades to column y of composite type collate_dep_test2
+drop cascades to view collate_dep_test3
+drop cascades to index collate_dep_test4i
+\d collate_dep_test1
+      Table "collate_tests.collate_dep_test1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+
+\d collate_dep_test2
+ Composite type "collate_tests.collate_dep_test2"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ x      | integer |           |          | 
+
+DROP TABLE collate_dep_test1, collate_dep_test4t;
+DROP TYPE collate_dep_test2;
+-- test range types and collations
+create type textrange_c as range(subtype=text, collation="C");
+create type textrange_en_us as range(subtype=text, collation="en_US");
+select textrange_c('A','Z') @> 'b'::text;
+ ?column? 
+----------
+ f
+(1 row)
+
+select textrange_en_us('A','Z') @> 'b'::text;
+ ?column? 
+----------
+ t
+(1 row)
+
+drop type textrange_c;
+drop type textrange_en_us;
+-- nondeterministic collations
+-- (not supported with libc provider)
+CREATE COLLATION ctest_det (locale = 'en_US', deterministic = true);
+CREATE COLLATION ctest_nondet (locale = 'en_US', deterministic = false);
+ERROR:  nondeterministic collations not supported with this provider
+-- cleanup
+SET client_min_messages TO warning;
+DROP SCHEMA collate_tests CASCADE;
diff --git a/src/test/regress/expected/collate.windows.win1252_1.out b/src/test/regress/expected/collate.windows.win1252_1.out
new file mode 100644
index 0000000..7e45476
--- /dev/null
+++ b/src/test/regress/expected/collate.windows.win1252_1.out
@@ -0,0 +1,12 @@
+/*
+ * This test is for Windows/Visual Studio systems and assumes that a full set
+ * of locales is installed. It must be run in a database with WIN1252 encoding,
+ * because of the locales' encondings. We lose some interesting cases from the
+ * UTF-8 version, like Turkish dotted and undotted 'i' or Greek sigma.
+ */
+SELECT getdatabaseencoding() <> 'WIN1252' OR
+       (SELECT count(*) FROM pg_collation WHERE collname IN ('de_DE', 'en_US', 'sv_SE') AND collencoding = pg_char_to_encoding('WIN1252')) <> 3 OR
+       version() !~ 'Visual C\+\+'
+       AS skip_test \gset
+\if :skip_test
+\quit
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 017e962..0e1c853 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -91,7 +91,7 @@ test: create_table_like alter_generic alter_operator misc async dbsize misc_func
 # rules cannot run concurrently with any test that creates
 # a view or rule in the public schema
 # collate.*.utf8 tests cannot be run in parallel with each other
-test: rules psql psql_crosstab amutils stats_ext collate.linux.utf8
+test: rules psql psql_crosstab amutils stats_ext collate.linux.utf8 collate.windows.win1252
 
 # run by itself so it can run parallel workers
 test: select_parallel
diff --git a/src/test/regress/sql/collate.windows.win1252.sql b/src/test/regress/sql/collate.windows.win1252.sql
new file mode 100644
index 0000000..e0e5cea
--- /dev/null
+++ b/src/test/regress/sql/collate.windows.win1252.sql
@@ -0,0 +1,418 @@
+/*
+ * This test is for Windows/Visual Studio systems and assumes that a full set
+ * of locales is installed. It must be run in a database with WIN1252 encoding,
+ * because of the locales' encondings. We lose some interesting cases from the
+ * UTF-8 version, like Turkish dotted and undotted 'i' or Greek sigma.
+ */
+SELECT getdatabaseencoding() <> 'WIN1252' OR
+       (SELECT count(*) FROM pg_collation WHERE collname IN ('de_DE', 'en_US', 'sv_SE') AND collencoding = pg_char_to_encoding('WIN1252')) <> 3 OR
+       version() !~ 'Visual C\+\+'
+       AS skip_test \gset
+\if :skip_test
+\quit
+\endif
+
+SET client_encoding TO WIN1252;
+
+CREATE SCHEMA collate_tests;
+SET search_path = collate_tests;
+
+
+CREATE TABLE collate_test1 (
+    a int,
+    b text COLLATE "en_US" NOT NULL
+);
+
+\d collate_test1
+
+CREATE TABLE collate_test_fail (
+    a int,
+    b text COLLATE "ja_JP.eucjp"
+);
+
+CREATE TABLE collate_test_fail (
+    a int,
+    b text COLLATE "foo"
+);
+
+CREATE TABLE collate_test_fail (
+    a int COLLATE "en_US",
+    b text
+);
+
+CREATE TABLE collate_test_like (
+    LIKE collate_test1
+);
+
+\d collate_test_like
+
+CREATE TABLE collate_test2 (
+    a int,
+    b text COLLATE "sv_SE"
+);
+
+CREATE TABLE collate_test3 (
+    a int,
+    b text COLLATE "C"
+);
+
+INSERT INTO collate_test1 VALUES (1, 'abc'), (2, '�bc'), (3, 'bbc'), (4, 'ABC');
+INSERT INTO collate_test2 SELECT * FROM collate_test1;
+INSERT INTO collate_test3 SELECT * FROM collate_test1;
+
+SELECT * FROM collate_test1 WHERE b >= 'bbc';
+SELECT * FROM collate_test2 WHERE b >= 'bbc';
+SELECT * FROM collate_test3 WHERE b >= 'bbc';
+SELECT * FROM collate_test3 WHERE b >= 'BBC';
+
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc';
+SELECT * FROM collate_test1 WHERE b >= 'bbc' COLLATE "C";
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "C";
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "en_US";
+
+
+CREATE DOMAIN testdomain_sv AS text COLLATE "sv_SE";
+CREATE DOMAIN testdomain_i AS int COLLATE "sv_SE"; -- fails
+CREATE TABLE collate_test4 (
+    a int,
+    b testdomain_sv
+);
+INSERT INTO collate_test4 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test4 ORDER BY b;
+
+CREATE TABLE collate_test5 (
+    a int,
+    b testdomain_sv COLLATE "en_US"
+);
+INSERT INTO collate_test5 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test5 ORDER BY b;
+
+
+SELECT a, b FROM collate_test1 ORDER BY b;
+SELECT a, b FROM collate_test2 ORDER BY b;
+SELECT a, b FROM collate_test3 ORDER BY b;
+
+SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+
+-- star expansion
+SELECT * FROM collate_test1 ORDER BY b;
+SELECT * FROM collate_test2 ORDER BY b;
+SELECT * FROM collate_test3 ORDER BY b;
+
+-- constant expression folding
+SELECT 'bbc' COLLATE "en_US" > '�bc' COLLATE "en_US" AS "true";
+SELECT 'bbc' COLLATE "sv_SE" > '�bc' COLLATE "sv_SE" AS "false";
+
+-- LIKE/ILIKE
+
+SELECT * FROM collate_test1 WHERE b LIKE 'abc';
+SELECT * FROM collate_test1 WHERE b LIKE 'abc%';
+SELECT * FROM collate_test1 WHERE b LIKE '%bc%';
+SELECT * FROM collate_test1 WHERE b ILIKE 'abc';
+SELECT * FROM collate_test1 WHERE b ILIKE 'abc%';
+SELECT * FROM collate_test1 WHERE b ILIKE '%bc%';
+
+
+-- The following actually exercises the selectivity estimation for ILIKE.
+SELECT relname FROM pg_class WHERE relname ILIKE 'abc%';
+
+-- regular expressions
+
+SELECT * FROM collate_test1 WHERE b ~ '^abc$';
+SELECT * FROM collate_test1 WHERE b ~ '^abc';
+SELECT * FROM collate_test1 WHERE b ~ 'bc';
+SELECT * FROM collate_test1 WHERE b ~* '^abc$';
+SELECT * FROM collate_test1 WHERE b ~* '^abc';
+SELECT * FROM collate_test1 WHERE b ~* 'bc';
+
+CREATE TABLE collate_test6 (
+    a int,
+    b text COLLATE "en_US"
+);
+INSERT INTO collate_test6 VALUES (1, 'abc'), (2, 'ABC'), (3, '123'), (4, 'ab1'),
+                                 (5, 'a1!'), (6, 'a c'), (7, '!.;'), (8, '   '),
+                                 (9, '�b�'), (10, '�B�');
+SELECT b,
+       b ~ '^[[:alpha:]]+$' AS is_alpha,
+       b ~ '^[[:upper:]]+$' AS is_upper,
+       b ~ '^[[:lower:]]+$' AS is_lower,
+       b ~ '^[[:digit:]]+$' AS is_digit,
+       b ~ '^[[:alnum:]]+$' AS is_alnum,
+       b ~ '^[[:graph:]]+$' AS is_graph,
+       b ~ '^[[:print:]]+$' AS is_print,
+       b ~ '^[[:punct:]]+$' AS is_punct,
+       b ~ '^[[:space:]]+$' AS is_space
+FROM collate_test6;
+
+
+-- The following actually exercises the selectivity estimation for ~*.
+SELECT relname FROM pg_class WHERE relname ~* '^abc';
+
+
+-- to_char
+
+SET lc_time TO 'de_DE';
+SELECT to_char(date '2010-03-01', 'DD TMMON YYYY');
+SELECT to_char(date '2010-03-01', 'DD TMMON YYYY' COLLATE "de_DE");
+
+-- to_date
+
+SELECT to_date('01 M�R 2010', 'DD TMMON YYYY');
+SELECT to_date('01 M�r 2010', 'DD TMMON YYYY');
+SELECT to_date('1234567890ab 2010', 'TMMONTH YYYY'); -- fail
+
+
+-- backwards parsing
+
+CREATE VIEW collview1 AS SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc';
+CREATE VIEW collview2 AS SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+
+SELECT table_name, view_definition FROM information_schema.views
+  WHERE table_name LIKE 'collview%' ORDER BY 1;
+
+
+-- collation propagation in various expression types
+
+SELECT a, coalesce(b, 'foo') FROM collate_test1 ORDER BY 2;
+SELECT a, coalesce(b, 'foo') FROM collate_test2 ORDER BY 2;
+SELECT a, coalesce(b, 'foo') FROM collate_test3 ORDER BY 2;
+
+SELECT a, b, greatest(b, 'CCC') FROM collate_test1 ORDER BY 3;
+SELECT a, b, greatest(b, 'CCC') FROM collate_test2 ORDER BY 3;
+SELECT a, b, greatest(b, 'CCC') FROM collate_test3 ORDER BY 3;
+
+SELECT a, nullif(b, 'abc') FROM collate_test1 ORDER BY 2;
+SELECT a, nullif(b, 'abc') FROM collate_test2 ORDER BY 2;
+SELECT a, nullif(b, 'abc') FROM collate_test3 ORDER BY 2;
+
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test1 ORDER BY 2;
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test2 ORDER BY 2;
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test3 ORDER BY 2;
+
+CREATE DOMAIN testdomain AS text;
+SELECT a, b::testdomain FROM collate_test1 ORDER BY 2;
+SELECT a, b::testdomain FROM collate_test2 ORDER BY 2;
+SELECT a, b::testdomain FROM collate_test3 ORDER BY 2;
+SELECT a, b::testdomain_sv FROM collate_test3 ORDER BY 2;
+
+SELECT min(b), max(b) FROM collate_test1;
+SELECT min(b), max(b) FROM collate_test2;
+SELECT min(b), max(b) FROM collate_test3;
+
+SELECT array_agg(b ORDER BY b) FROM collate_test1;
+SELECT array_agg(b ORDER BY b) FROM collate_test2;
+SELECT array_agg(b ORDER BY b) FROM collate_test3;
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test1 ORDER BY 2;
+SELECT a, b FROM collate_test2 UNION SELECT a, b FROM collate_test2 ORDER BY 2;
+SELECT a, b FROM collate_test3 WHERE a < 4 INTERSECT SELECT a, b FROM collate_test3 WHERE a > 1 ORDER BY 2;
+SELECT a, b FROM collate_test3 EXCEPT SELECT a, b FROM collate_test3 WHERE a < 2 ORDER BY 2;
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3; -- ok
+SELECT a, b FROM collate_test1 UNION SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+SELECT a, b COLLATE "C" FROM collate_test1 UNION SELECT a, b FROM collate_test3 ORDER BY 2; -- ok
+SELECT a, b FROM collate_test1 INTERSECT SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+SELECT a, b FROM collate_test1 EXCEPT SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+
+CREATE TABLE test_u AS SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3; -- fail
+
+-- collation mismatch between recursive and non-recursive term
+WITH RECURSIVE foo(x) AS
+   (SELECT x FROM (VALUES('a' COLLATE "en_US"),('b')) t(x)
+   UNION ALL
+   SELECT (x || 'c') COLLATE "de_DE" FROM foo WHERE length(x) < 10)
+SELECT * FROM foo;
+
+
+-- casting
+
+SELECT CAST('42' AS text COLLATE "C");
+
+SELECT a, CAST(b AS varchar) FROM collate_test1 ORDER BY 2;
+SELECT a, CAST(b AS varchar) FROM collate_test2 ORDER BY 2;
+SELECT a, CAST(b AS varchar) FROM collate_test3 ORDER BY 2;
+
+
+-- propagation of collation in SQL functions (inlined and non-inlined cases)
+-- and plpgsql functions too
+
+CREATE FUNCTION mylt (text, text) RETURNS boolean LANGUAGE sql
+    AS $$ select $1 < $2 $$;
+
+CREATE FUNCTION mylt_noninline (text, text) RETURNS boolean LANGUAGE sql
+    AS $$ select $1 < $2 limit 1 $$;
+
+CREATE FUNCTION mylt_plpgsql (text, text) RETURNS boolean LANGUAGE plpgsql
+    AS $$ begin return $1 < $2; end $$;
+
+SELECT a.b AS a, b.b AS b, a.b < b.b AS lt,
+       mylt(a.b, b.b), mylt_noninline(a.b, b.b), mylt_plpgsql(a.b, b.b)
+FROM collate_test1 a, collate_test1 b
+ORDER BY a.b, b.b;
+
+SELECT a.b AS a, b.b AS b, a.b < b.b COLLATE "C" AS lt,
+       mylt(a.b, b.b COLLATE "C"), mylt_noninline(a.b, b.b COLLATE "C"),
+       mylt_plpgsql(a.b, b.b COLLATE "C")
+FROM collate_test1 a, collate_test1 b
+ORDER BY a.b, b.b;
+
+
+-- collation override in plpgsql
+
+CREATE FUNCTION mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+  xx text := x;
+  yy text := y;
+begin
+  return xx < yy;
+end
+$$;
+
+SELECT mylt2('a', 'B' collate "en_US") as t, mylt2('a', 'B' collate "C") as f;
+
+CREATE OR REPLACE FUNCTION
+  mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+  xx text COLLATE "POSIX" := x;
+  yy text := y;
+begin
+  return xx < yy;
+end
+$$;
+
+SELECT mylt2('a', 'B') as f;
+SELECT mylt2('a', 'B' collate "C") as fail; -- conflicting collations
+SELECT mylt2('a', 'B' collate "POSIX") as f;
+
+
+-- polymorphism
+
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test1)) ORDER BY 1;
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test2)) ORDER BY 1;
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test3)) ORDER BY 1;
+
+CREATE FUNCTION dup (anyelement) RETURNS anyelement
+    AS 'select $1' LANGUAGE sql;
+
+SELECT a, dup(b) FROM collate_test1 ORDER BY 2;
+SELECT a, dup(b) FROM collate_test2 ORDER BY 2;
+SELECT a, dup(b) FROM collate_test3 ORDER BY 2;
+
+
+-- indexes
+
+CREATE INDEX collate_test1_idx1 ON collate_test1 (b);
+CREATE INDEX collate_test1_idx2 ON collate_test1 (b COLLATE "C");
+CREATE INDEX collate_test1_idx3 ON collate_test1 ((b COLLATE "C")); -- this is different grammatically
+CREATE INDEX collate_test1_idx4 ON collate_test1 (((b||'foo') COLLATE "POSIX"));
+
+CREATE INDEX collate_test1_idx5 ON collate_test1 (a COLLATE "C"); -- fail
+CREATE INDEX collate_test1_idx6 ON collate_test1 ((a COLLATE "C")); -- fail
+
+SELECT relname, pg_get_indexdef(oid) FROM pg_class WHERE relname LIKE 'collate_test%_idx%' ORDER BY 1;
+
+
+-- schema manipulation commands
+
+CREATE ROLE regress_test_role;
+CREATE SCHEMA test_schema;
+
+-- We need to do this this way to cope with varying names for encodings:
+do $$
+BEGIN
+  EXECUTE 'CREATE COLLATION test0 (locale = ' ||
+          quote_literal(current_setting('lc_collate')) || ');';
+END
+$$;
+CREATE COLLATION test0 FROM "C"; -- fail, duplicate name
+CREATE COLLATION IF NOT EXISTS test0 FROM "C"; -- ok, skipped
+CREATE COLLATION IF NOT EXISTS test0 (locale = 'foo'); -- ok, skipped
+do $$
+BEGIN
+  EXECUTE 'CREATE COLLATION test1 (lc_collate = ' ||
+          quote_literal(current_setting('lc_collate')) ||
+          ', lc_ctype = ' ||
+          quote_literal(current_setting('lc_ctype')) || ');';
+END
+$$;
+CREATE COLLATION test3 (lc_collate = 'en_US.utf8'); -- fail, need lc_ctype
+CREATE COLLATION testx (locale = 'nonsense'); -- fail
+
+CREATE COLLATION test4 FROM nonsense;
+CREATE COLLATION test5 FROM test0;
+
+SELECT collname FROM pg_collation WHERE collname LIKE 'test%' ORDER BY 1;
+
+ALTER COLLATION test1 RENAME TO test11;
+ALTER COLLATION test0 RENAME TO test11; -- fail
+ALTER COLLATION test1 RENAME TO test22; -- fail
+
+ALTER COLLATION test11 OWNER TO regress_test_role;
+ALTER COLLATION test11 OWNER TO nonsense;
+ALTER COLLATION test11 SET SCHEMA test_schema;
+
+COMMENT ON COLLATION test0 IS 'US English';
+
+SELECT collname, nspname, obj_description(pg_collation.oid, 'pg_collation')
+    FROM pg_collation JOIN pg_namespace ON (collnamespace = pg_namespace.oid)
+    WHERE collname LIKE 'test%'
+    ORDER BY 1;
+
+DROP COLLATION test0, test_schema.test11, test5;
+DROP COLLATION test0; -- fail
+DROP COLLATION IF EXISTS test0;
+
+SELECT collname FROM pg_collation WHERE collname LIKE 'test%';
+
+DROP SCHEMA test_schema;
+DROP ROLE regress_test_role;
+
+
+-- ALTER
+
+ALTER COLLATION "en_US" REFRESH VERSION;
+
+
+-- dependencies
+
+CREATE COLLATION test0 FROM "C";
+
+CREATE TABLE collate_dep_test1 (a int, b text COLLATE test0);
+CREATE DOMAIN collate_dep_dom1 AS text COLLATE test0;
+CREATE TYPE collate_dep_test2 AS (x int, y text COLLATE test0);
+CREATE VIEW collate_dep_test3 AS SELECT text 'foo' COLLATE test0 AS foo;
+CREATE TABLE collate_dep_test4t (a int, b text);
+CREATE INDEX collate_dep_test4i ON collate_dep_test4t (b COLLATE test0);
+
+DROP COLLATION test0 RESTRICT; -- fail
+DROP COLLATION test0 CASCADE;
+
+\d collate_dep_test1
+\d collate_dep_test2
+
+DROP TABLE collate_dep_test1, collate_dep_test4t;
+DROP TYPE collate_dep_test2;
+
+-- test range types and collations
+
+create type textrange_c as range(subtype=text, collation="C");
+create type textrange_en_us as range(subtype=text, collation="en_US");
+
+select textrange_c('A','Z') @> 'b'::text;
+select textrange_en_us('A','Z') @> 'b'::text;
+
+drop type textrange_c;
+drop type textrange_en_us;
+
+
+-- nondeterministic collations
+-- (not supported with libc provider)
+
+CREATE COLLATION ctest_det (locale = 'en_US', deterministic = true);
+CREATE COLLATION ctest_nondet (locale = 'en_US', deterministic = false);
+
+
+-- cleanup
+SET client_min_messages TO warning;
+DROP SCHEMA collate_tests CASCADE;
diff --git a/src/tools/msvc/vcregress.pl b/src/tools/msvc/vcregress.pl
index 5975e7c..ea2add2 100644
--- a/src/tools/msvc/vcregress.pl
+++ b/src/tools/msvc/vcregress.pl
@@ -154,6 +154,7 @@ sub installcheck
 sub check
 {
 	my $schedule = shift || 'parallel';
+	my $encoding = $ENV{ENCODING} || "SQL_ASCII";
 	# for backwards compatibility, "serial" runs the tests in
 	# parallel_schedule one by one.
 	my $maxconn = $maxconn;
@@ -169,7 +170,7 @@ sub check
 		"--schedule=${schedule}_schedule",
 		"--max-concurrent-tests=20",
 		"--make-testtablespace-dir",
-		"--encoding=SQL_ASCII",
+		"--encoding=${encoding}",
 		"--no-locale",
 		"--temp-instance=./tmp_check");
 	push(@args, $maxconn)     if $maxconn;
-- 
2.11.0

From dd572aae14adfb262dc38bd0e011bf910cdd4f12 Mon Sep 17 00:00:00 2001
From: Juan Jose Santamaria Flecha <juanjo.santamaria@gmail.com>
Date: Wed, 19 Jan 2022 07:15:15 -0500
Subject: [PATCH] WIN32 pg_import_system_collations . Adds the
 pg_import_system_collations() functionality for Windows newer than 2008 using
 EnumSystemLocalesEx(). Also adding a test emulating collate.linux.utf8 but
 for Windows-1252

---
 src/backend/commands/collationcmds.c               |  197 +++-
 .../regress/expected/collate.windows.win1252.out   | 1020 ++++++++++++++++++++
 .../regress/expected/collate.windows.win1252_1.out |   13 +
 src/test/regress/parallel_schedule                 |    2 +-
 src/test/regress/sql/collate.windows.win1252.sql   |  419 ++++++++
 src/tools/msvc/vcregress.pl                        |    3 +-
 6 files changed, 1602 insertions(+), 52 deletions(-)
 create mode 100644 src/test/regress/expected/collate.windows.win1252.out
 create mode 100644 src/test/regress/expected/collate.windows.win1252_1.out
 create mode 100644 src/test/regress/sql/collate.windows.win1252.sql

diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index 5674855..a1589c5 100644
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -522,6 +522,128 @@ get_icu_locale_comment(const char *localename)
 }
 #endif							/* USE_ICU */
 
+/* will we use EnumSystemLocalesEx in pg_import_system_collations? */
+#if defined(WIN32) && _WIN32_WINNT >= 0x0600
+#define ENUM_SYSTEM_LOCALE
+#endif
+
+#if defined(READ_LOCALE_A_OUTPUT) || defined(ENUM_SYSTEM_LOCALE)
+/*
+ * Create a collation if the input locale is valid for so.
+ * Also keeps track of the number of valid locales and collations created.
+ */
+static int
+CollationFromLocale(char *localebuf, int *nvalid, int *ncreated, int nspid)
+{
+	int			enc;
+	Oid			collid;
+
+	/*
+	 * Some systems have locale names that don't consist entirely of
+	 * ASCII letters (such as "bokm&aring;l" or "fran&ccedil;ais").
+	 * This is pretty silly, since we need the locale itself to
+	 * interpret the non-ASCII characters. We can't do much with
+	 * those, so we filter them out.
+	 */
+	if (!pg_is_ascii(localebuf))
+	{
+		elog(DEBUG1, "skipping locale with non-ASCII name: \"%s\"", localebuf);
+		return -1;
+	}
+
+	enc = pg_get_encoding_from_locale(localebuf, false);
+	if (enc < 0)
+	{
+		elog(DEBUG1, "skipping locale with unrecognized encoding: \"%s\"",
+			 localebuf);
+		return -1;
+	}
+	if (!PG_VALID_BE_ENCODING(enc))
+	{
+		elog(DEBUG1, "skipping locale with client-only encoding: \"%s\"", localebuf);
+		return -1;
+	}
+	if (enc == PG_SQL_ASCII)
+		return -1;		/* C/POSIX are already in the catalog */
+
+	/* count valid locales found in operating system */
+	*nvalid += 1;
+
+	/*
+	 * Create a collation named the same as the locale, but quietly
+	 * doing nothing if it already exists.  This is the behavior we
+	 * need even at initdb time, because some versions of "locale -a"
+	 * can report the same locale name more than once.  And it's
+	 * convenient for later import runs, too, since you just about
+	 * always want to add on new locales without a lot of chatter
+	 * about existing ones.
+	 */
+	collid = CollationCreate(localebuf, nspid, GetUserId(),
+							 COLLPROVIDER_LIBC, true, enc,
+							 localebuf, localebuf,
+							 get_collation_actual_version(COLLPROVIDER_LIBC, localebuf),
+							 true, true);
+	if (OidIsValid(collid))
+	{
+		*ncreated += 1;
+
+		/* Must do CCI between inserts to handle duplicates correctly */
+		CommandCounterIncrement();
+	}
+
+	return enc;
+}
+#endif							/* defined(READ_LOCALE_A_OUTPUT) || defined(ENUM_SYSTEM_LOCALE) */
+
+#ifdef ENUM_SYSTEM_LOCALE
+/* Parameter to be passed to the callback function win32_read_locale() */
+typedef struct
+{
+	int		   *ncreated;
+	int		   *nvalid;
+	Oid			nspid;
+} CollParam;
+
+/*
+ * Callback function for EnumSystemLocalesEx() in pg_import_system_collations()
+ * Creates a collation for every valid locale.
+ */
+BOOL CALLBACK
+win32_read_locale(LPWSTR pStr, DWORD dwFlags, LPARAM lparam)
+{
+	CollParam  *param = (CollParam *) lparam;
+	char		localebuf[NAMEDATALEN];
+	int			result;
+	char	   *hyphen;
+
+	(void) dwFlags;
+
+	result = WideCharToMultiByte(CP_ACP, 0, pStr, -1, localebuf, NAMEDATALEN,
+								 NULL, NULL);
+
+	if (result == 0)
+	{
+		if (GetLastError() == ERROR_INSUFFICIENT_BUFFER)
+			elog(DEBUG1, "skipping locale with too-long name: \"%s\"", localebuf);
+		return (TRUE);
+	}
+	if (localebuf[0] == '\0')
+		return (TRUE);
+
+	/*
+	 * Windows will use hyphens between language and territory, where POSIX
+	 * uses an underscore. Simply make it POSIX looking.
+	 */
+	hyphen = strchr(localebuf, '-');
+	if (hyphen)
+		*hyphen = '_';
+
+	CollationFromLocale(localebuf, param->nvalid, param->ncreated, param->nspid);
+
+	return (TRUE);
+}
+#endif							/* ENUM_SYSTEM_LOCALE */
+
 
 /*
  * pg_import_system_collations: add known system collations to pg_collation
@@ -581,58 +703,9 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 			}
 			localebuf[len - 1] = '\0';
 
-			/*
-			 * Some systems have locale names that don't consist entirely of
-			 * ASCII letters (such as "bokm&aring;l" or "fran&ccedil;ais").
-			 * This is pretty silly, since we need the locale itself to
-			 * interpret the non-ASCII characters. We can't do much with
-			 * those, so we filter them out.
-			 */
-			if (!pg_is_ascii(localebuf))
-			{
-				elog(DEBUG1, "skipping locale with non-ASCII name: \"%s\"", localebuf);
-				continue;
-			}
-
-			enc = pg_get_encoding_from_locale(localebuf, false);
+			enc = CollationFromLocale(localebuf, &nvalid, &ncreated, nspid);
 			if (enc < 0)
-			{
-				elog(DEBUG1, "skipping locale with unrecognized encoding: \"%s\"",
-					 localebuf);
-				continue;
-			}
-			if (!PG_VALID_BE_ENCODING(enc))
-			{
-				elog(DEBUG1, "skipping locale with client-only encoding: \"%s\"", localebuf);
 				continue;
-			}
-			if (enc == PG_SQL_ASCII)
-				continue;		/* C/POSIX are already in the catalog */
-
-			/* count valid locales found in operating system */
-			nvalid++;
-
-			/*
-			 * Create a collation named the same as the locale, but quietly
-			 * doing nothing if it already exists.  This is the behavior we
-			 * need even at initdb time, because some versions of "locale -a"
-			 * can report the same locale name more than once.  And it's
-			 * convenient for later import runs, too, since you just about
-			 * always want to add on new locales without a lot of chatter
-			 * about existing ones.
-			 */
-			collid = CollationCreate(localebuf, nspid, GetUserId(),
-									 COLLPROVIDER_LIBC, true, enc,
-									 localebuf, localebuf,
-									 get_collation_actual_version(COLLPROVIDER_LIBC, localebuf),
-									 true, true);
-			if (OidIsValid(collid))
-			{
-				ncreated++;
-
-				/* Must do CCI between inserts to handle duplicates correctly */
-				CommandCounterIncrement();
-			}
 
 			/*
 			 * Generate aliases such as "en_US" in addition to "en_US.utf8"
@@ -702,6 +775,30 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
 	}
 #endif							/* READ_LOCALE_A_OUTPUT */
 
+	/* Load collations known to WIN32 */
+#ifdef ENUM_SYSTEM_LOCALE
+	{
+		int			nvalid = 0;
+		CollParam	param;
+		param.ncreated = &ncreated;
+		param.nvalid = &nvalid;
+		param.nspid = nspid;
+
+		/*
+		 * Enumerate the locales that are either installed on or supported
+		 * by the OS.
+		 */
+		if (!EnumSystemLocalesEx(win32_read_locale, LOCALE_ALL,
+								 (LPARAM) &param, NULL))
+			_dosmaperr(GetLastError());
+
+		/* Give a warning if EnumSystemLocalesEx seems to be malfunctioning */
+		if (nvalid == 0)
+			ereport(WARNING,
+					(errmsg("no usable system locales were found")));
+	}
+#endif							/* ENUM_SYSTEM_LOCALE */
+
 	/*
 	 * Load collations known to ICU
 	 *
diff --git a/src/test/regress/expected/collate.windows.win1252.out b/src/test/regress/expected/collate.windows.win1252.out
new file mode 100644
index 0000000..1245c11
--- /dev/null
+++ b/src/test/regress/expected/collate.windows.win1252.out
@@ -0,0 +1,1020 @@
+/*
+ * This test is meant to run on Windows systems that has successfully run
+ * pg_import_system_collations(). This is possible for builds with a minimum
+ * system version of Windows Vista, and onwards. Also, the database must have
+ * WIN1252 encoding, because of the locales' own encodings. Due to this, some
+ * test are lost from UTF-8 version, like Turkish dotted and undotted 'i'.
+ */
+SELECT getdatabaseencoding() <> 'WIN1252' OR
+       (SELECT count(*) FROM pg_collation WHERE collname IN ('de_DE', 'en_US', 'sv_SE') AND collencoding = pg_char_to_encoding('WIN1252')) <> 3 OR
+       version() !~ 'Visual C\+\+'
+       AS skip_test \gset
+\if :skip_test
+\quit
+\endif
+SET client_encoding TO WIN1252;
+CREATE SCHEMA collate_tests;
+SET search_path = collate_tests;
+CREATE TABLE collate_test1 (
+    a int,
+    b text COLLATE "en_US" NOT NULL
+);
+\d collate_test1
+        Table "collate_tests.collate_test1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | text    | en_US     | not null | 
+
+CREATE TABLE collate_test_fail (
+    a int,
+    b text COLLATE "ja_JP.eucjp"
+);
+ERROR:  collation "ja_JP.eucjp" for encoding "WIN1252" does not exist
+LINE 3:     b text COLLATE "ja_JP.eucjp"
+                   ^
+CREATE TABLE collate_test_fail (
+    a int,
+    b text COLLATE "foo"
+);
+ERROR:  collation "foo" for encoding "WIN1252" does not exist
+LINE 3:     b text COLLATE "foo"
+                   ^
+CREATE TABLE collate_test_fail (
+    a int COLLATE "en_US",
+    b text
+);
+ERROR:  collations are not supported by type integer
+LINE 2:     a int COLLATE "en_US",
+                  ^
+CREATE TABLE collate_test_like (
+    LIKE collate_test1
+);
+\d collate_test_like
+      Table "collate_tests.collate_test_like"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+ b      | text    | en_US     | not null | 
+
+CREATE TABLE collate_test2 (
+    a int,
+    b text COLLATE "sv_SE"
+);
+CREATE TABLE collate_test3 (
+    a int,
+    b text COLLATE "C"
+);
+INSERT INTO collate_test1 VALUES (1, 'abc'), (2, '�bc'), (3, 'bbc'), (4, 'ABC');
+INSERT INTO collate_test2 SELECT * FROM collate_test1;
+INSERT INTO collate_test3 SELECT * FROM collate_test1;
+SELECT * FROM collate_test1 WHERE b >= 'bbc';
+ a |  b  
+---+-----
+ 3 | bbc
+(1 row)
+
+SELECT * FROM collate_test2 WHERE b >= 'bbc';
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test3 WHERE b >= 'bbc';
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test3 WHERE b >= 'BBC';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+(3 rows)
+
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc';
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b >= 'bbc' COLLATE "C";
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "C";
+ a |  b  
+---+-----
+ 2 | �bc
+ 3 | bbc
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "en_US";
+ERROR:  collation mismatch between explicit collations "C" and "en_US"
+LINE 1: ...* FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "e...
+                                                             ^
+CREATE DOMAIN testdomain_sv AS text COLLATE "sv_SE";
+CREATE DOMAIN testdomain_i AS int COLLATE "sv_SE"; -- fails
+ERROR:  collations are not supported by type integer
+CREATE TABLE collate_test4 (
+    a int,
+    b testdomain_sv
+);
+INSERT INTO collate_test4 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test4 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+CREATE TABLE collate_test5 (
+    a int,
+    b testdomain_sv COLLATE "en_US"
+);
+INSERT INTO collate_test5 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test5 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, b FROM collate_test1 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, b FROM collate_test2 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b FROM collate_test3 ORDER BY b;
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+-- star expansion
+SELECT * FROM collate_test1 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT * FROM collate_test2 ORDER BY b;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT * FROM collate_test3 ORDER BY b;
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+-- constant expression folding
+SELECT 'bbc' COLLATE "en_US" > '�bc' COLLATE "en_US" AS "true";
+ true 
+------
+ t
+(1 row)
+
+SELECT 'bbc' COLLATE "sv_SE" > '�bc' COLLATE "sv_SE" AS "false";
+ false 
+-------
+ f
+(1 row)
+
+-- LIKE/ILIKE
+SELECT * FROM collate_test1 WHERE b LIKE 'abc';
+ a |  b  
+---+-----
+ 1 | abc
+(1 row)
+
+SELECT * FROM collate_test1 WHERE b LIKE 'abc%';
+ a |  b  
+---+-----
+ 1 | abc
+(1 row)
+
+SELECT * FROM collate_test1 WHERE b LIKE '%bc%';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+(3 rows)
+
+SELECT * FROM collate_test1 WHERE b ILIKE 'abc';
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b ILIKE 'abc%';
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b ILIKE '%bc%';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+ 4 | ABC
+(4 rows)
+
+-- The following actually exercises the selectivity estimation for ILIKE.
+SELECT relname FROM pg_class WHERE relname ILIKE 'abc%';
+ relname 
+---------
+(0 rows)
+
+-- regular expressions
+SELECT * FROM collate_test1 WHERE b ~ '^abc$';
+ a |  b  
+---+-----
+ 1 | abc
+(1 row)
+
+SELECT * FROM collate_test1 WHERE b ~ '^abc';
+ a |  b  
+---+-----
+ 1 | abc
+(1 row)
+
+SELECT * FROM collate_test1 WHERE b ~ 'bc';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+(3 rows)
+
+SELECT * FROM collate_test1 WHERE b ~* '^abc$';
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b ~* '^abc';
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+(2 rows)
+
+SELECT * FROM collate_test1 WHERE b ~* 'bc';
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+ 4 | ABC
+(4 rows)
+
+CREATE TABLE collate_test6 (
+    a int,
+    b text COLLATE "en_US"
+);
+INSERT INTO collate_test6 VALUES (1, 'abc'), (2, 'ABC'), (3, '123'), (4, 'ab1'),
+                                 (5, 'a1!'), (6, 'a c'), (7, '!.;'), (8, '   '),
+                                 (9, '�b�'), (10, '�B�');
+SELECT b,
+       b ~ '^[[:alpha:]]+$' AS is_alpha,
+       b ~ '^[[:upper:]]+$' AS is_upper,
+       b ~ '^[[:lower:]]+$' AS is_lower,
+       b ~ '^[[:digit:]]+$' AS is_digit,
+       b ~ '^[[:alnum:]]+$' AS is_alnum,
+       b ~ '^[[:graph:]]+$' AS is_graph,
+       b ~ '^[[:print:]]+$' AS is_print,
+       b ~ '^[[:punct:]]+$' AS is_punct,
+       b ~ '^[[:space:]]+$' AS is_space
+FROM collate_test6;
+  b  | is_alpha | is_upper | is_lower | is_digit | is_alnum | is_graph | is_print | is_punct | is_space 
+-----+----------+----------+----------+----------+----------+----------+----------+----------+----------
+ abc | t        | f        | t        | f        | t        | t        | t        | f        | f
+ ABC | t        | t        | f        | f        | t        | t        | t        | f        | f
+ 123 | f        | f        | f        | t        | t        | t        | t        | f        | f
+ ab1 | f        | f        | f        | f        | t        | t        | t        | f        | f
+ a1! | f        | f        | f        | f        | f        | t        | t        | f        | f
+ a c | f        | f        | f        | f        | f        | f        | t        | f        | f
+ !.; | f        | f        | f        | f        | f        | t        | t        | t        | f
+     | f        | f        | f        | f        | f        | f        | t        | f        | t
+ �b� | t        | f        | t        | f        | t        | t        | t        | f        | f
+ �B� | t        | t        | f        | f        | t        | t        | t        | f        | f
+(10 rows)
+
+-- The following actually exercises the selectivity estimation for ~*.
+SELECT relname FROM pg_class WHERE relname ~* '^abc';
+ relname 
+---------
+(0 rows)
+
+-- to_char
+SET lc_time TO 'de_DE';
+SELECT to_char(date '2010-03-01', 'DD TMMON YYYY');
+   to_char   
+-------------
+ 01 MRZ 2010
+(1 row)
+
+SELECT to_char(date '2010-03-01', 'DD TMMON YYYY' COLLATE "de_DE");
+   to_char   
+-------------
+ 01 MRZ 2010
+(1 row)
+
+-- to_date
+SELECT to_date('01 M�R 2010', 'DD TMMON YYYY');
+ERROR:  invalid value "M�R" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_date('01 M�r 2010', 'DD TMMON YYYY');
+ERROR:  invalid value "M�r" for "MON"
+DETAIL:  The given value did not match any of the allowed values for this field.
+SELECT to_date('1234567890ab 2010', 'TMMONTH YYYY'); -- fail
+ERROR:  invalid value "1234567890ab" for "MONTH"
+DETAIL:  The given value did not match any of the allowed values for this field.
+-- backwards parsing
+CREATE VIEW collview1 AS SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc';
+CREATE VIEW collview2 AS SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+SELECT table_name, view_definition FROM information_schema.views
+  WHERE table_name LIKE 'collview%' ORDER BY 1;
+ table_name |                     view_definition                     
+------------+---------------------------------------------------------
+ collview1  |  SELECT collate_test1.a,                               +
+            |     collate_test1.b                                    +
+            |    FROM collate_test1                                  +
+            |   WHERE ((collate_test1.b COLLATE "C") >= 'bbc'::text);
+ collview2  |  SELECT collate_test1.a,                               +
+            |     collate_test1.b                                    +
+            |    FROM collate_test1                                  +
+            |   ORDER BY (collate_test1.b COLLATE "C");
+(2 rows)
+
+-- collation propagation in various expression types
+SELECT a, coalesce(b, 'foo') FROM collate_test1 ORDER BY 2;
+ a | coalesce 
+---+----------
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, coalesce(b, 'foo') FROM collate_test2 ORDER BY 2;
+ a | coalesce 
+---+----------
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, coalesce(b, 'foo') FROM collate_test3 ORDER BY 2;
+ a | coalesce 
+---+----------
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b, greatest(b, 'CCC') FROM collate_test1 ORDER BY 3;
+ a |  b  | greatest 
+---+-----+----------
+ 1 | abc | CCC
+ 2 | �bc | CCC
+ 3 | bbc | CCC
+ 4 | ABC | CCC
+(4 rows)
+
+SELECT a, b, greatest(b, 'CCC') FROM collate_test2 ORDER BY 3;
+ a |  b  | greatest 
+---+-----+----------
+ 1 | abc | CCC
+ 3 | bbc | CCC
+ 4 | ABC | CCC
+ 2 | �bc | �bc
+(4 rows)
+
+SELECT a, b, greatest(b, 'CCC') FROM collate_test3 ORDER BY 3;
+ a |  b  | greatest 
+---+-----+----------
+ 4 | ABC | CCC
+ 1 | abc | abc
+ 3 | bbc | bbc
+ 2 | �bc | �bc
+(4 rows)
+
+SELECT a, nullif(b, 'abc') FROM collate_test1 ORDER BY 2;
+ a | nullif 
+---+--------
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+ 1 | 
+(4 rows)
+
+SELECT a, nullif(b, 'abc') FROM collate_test2 ORDER BY 2;
+ a | nullif 
+---+--------
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+ 1 | 
+(4 rows)
+
+SELECT a, nullif(b, 'abc') FROM collate_test3 ORDER BY 2;
+ a | nullif 
+---+--------
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+ 1 | 
+(4 rows)
+
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test1 ORDER BY 2;
+ a |  b   
+---+------
+ 4 | ABC
+ 2 | �bc
+ 1 | abcd
+ 3 | bbc
+(4 rows)
+
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test2 ORDER BY 2;
+ a |  b   
+---+------
+ 4 | ABC
+ 1 | abcd
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test3 ORDER BY 2;
+ a |  b   
+---+------
+ 4 | ABC
+ 1 | abcd
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+CREATE DOMAIN testdomain AS text;
+SELECT a, b::testdomain FROM collate_test1 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, b::testdomain FROM collate_test2 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b::testdomain FROM collate_test3 ORDER BY 2;
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b::testdomain_sv FROM collate_test3 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT min(b), max(b) FROM collate_test1;
+ min | max 
+-----+-----
+ abc | bbc
+(1 row)
+
+SELECT min(b), max(b) FROM collate_test2;
+ min | max 
+-----+-----
+ abc | �bc
+(1 row)
+
+SELECT min(b), max(b) FROM collate_test3;
+ min | max 
+-----+-----
+ ABC | �bc
+(1 row)
+
+SELECT array_agg(b ORDER BY b) FROM collate_test1;
+     array_agg     
+-------------------
+ {abc,ABC,�bc,bbc}
+(1 row)
+
+SELECT array_agg(b ORDER BY b) FROM collate_test2;
+     array_agg     
+-------------------
+ {abc,ABC,bbc,�bc}
+(1 row)
+
+SELECT array_agg(b ORDER BY b) FROM collate_test3;
+     array_agg     
+-------------------
+ {ABC,abc,bbc,�bc}
+(1 row)
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test1 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 1 | abc
+ 4 | ABC
+ 4 | ABC
+ 2 | �bc
+ 2 | �bc
+ 3 | bbc
+ 3 | bbc
+(8 rows)
+
+SELECT a, b FROM collate_test2 UNION SELECT a, b FROM collate_test2 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b FROM collate_test3 WHERE a < 4 INTERSECT SELECT a, b FROM collate_test3 WHERE a > 1 ORDER BY 2;
+ a |  b  
+---+-----
+ 3 | bbc
+ 2 | �bc
+(2 rows)
+
+SELECT a, b FROM collate_test3 EXCEPT SELECT a, b FROM collate_test3 WHERE a < 2 ORDER BY 2;
+ a |  b  
+---+-----
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(3 rows)
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+ERROR:  could not determine which collation to use for string comparison
+HINT:  Use the COLLATE clause to set the collation explicitly.
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3; -- ok
+ a |  b  
+---+-----
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+ 4 | ABC
+ 1 | abc
+ 2 | �bc
+ 3 | bbc
+ 4 | ABC
+(8 rows)
+
+SELECT a, b FROM collate_test1 UNION SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+ERROR:  collation mismatch between implicit collations "en_US" and "C"
+LINE 1: SELECT a, b FROM collate_test1 UNION SELECT a, b FROM collat...
+                                                       ^
+HINT:  You can choose the collation by applying the COLLATE clause to one or both expressions.
+SELECT a, b COLLATE "C" FROM collate_test1 UNION SELECT a, b FROM collate_test3 ORDER BY 2; -- ok
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, b FROM collate_test1 INTERSECT SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+ERROR:  collation mismatch between implicit collations "en_US" and "C"
+LINE 1: ...ELECT a, b FROM collate_test1 INTERSECT SELECT a, b FROM col...
+                                                             ^
+HINT:  You can choose the collation by applying the COLLATE clause to one or both expressions.
+SELECT a, b FROM collate_test1 EXCEPT SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+ERROR:  collation mismatch between implicit collations "en_US" and "C"
+LINE 1: SELECT a, b FROM collate_test1 EXCEPT SELECT a, b FROM colla...
+                                                        ^
+HINT:  You can choose the collation by applying the COLLATE clause to one or both expressions.
+CREATE TABLE test_u AS SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3; -- fail
+ERROR:  no collation was derived for column "b" with collatable type text
+HINT:  Use the COLLATE clause to set the collation explicitly.
+-- collation mismatch between recursive and non-recursive term
+WITH RECURSIVE foo(x) AS
+   (SELECT x FROM (VALUES('a' COLLATE "en_US"),('b')) t(x)
+   UNION ALL
+   SELECT (x || 'c') COLLATE "de_DE" FROM foo WHERE length(x) < 10)
+SELECT * FROM foo;
+ERROR:  recursive query "foo" column 1 has collation "en_US" in non-recursive term but collation "de_DE" overall
+LINE 2:    (SELECT x FROM (VALUES('a' COLLATE "en_US"),('b')) t(x)
+                   ^
+HINT:  Use the COLLATE clause to set the collation of the non-recursive term.
+-- casting
+SELECT CAST('42' AS text COLLATE "C");
+ERROR:  syntax error at or near "COLLATE"
+LINE 1: SELECT CAST('42' AS text COLLATE "C");
+                                 ^
+SELECT a, CAST(b AS varchar) FROM collate_test1 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, CAST(b AS varchar) FROM collate_test2 ORDER BY 2;
+ a |  b  
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, CAST(b AS varchar) FROM collate_test3 ORDER BY 2;
+ a |  b  
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+-- propagation of collation in SQL functions (inlined and non-inlined cases)
+-- and plpgsql functions too
+CREATE FUNCTION mylt (text, text) RETURNS boolean LANGUAGE sql
+    AS $$ select $1 < $2 $$;
+CREATE FUNCTION mylt_noninline (text, text) RETURNS boolean LANGUAGE sql
+    AS $$ select $1 < $2 limit 1 $$;
+CREATE FUNCTION mylt_plpgsql (text, text) RETURNS boolean LANGUAGE plpgsql
+    AS $$ begin return $1 < $2; end $$;
+SELECT a.b AS a, b.b AS b, a.b < b.b AS lt,
+       mylt(a.b, b.b), mylt_noninline(a.b, b.b), mylt_plpgsql(a.b, b.b)
+FROM collate_test1 a, collate_test1 b
+ORDER BY a.b, b.b;
+  a  |  b  | lt | mylt | mylt_noninline | mylt_plpgsql 
+-----+-----+----+------+----------------+--------------
+ abc | abc | f  | f    | f              | f
+ abc | ABC | t  | t    | t              | t
+ abc | �bc | t  | t    | t              | t
+ abc | bbc | t  | t    | t              | t
+ ABC | abc | f  | f    | f              | f
+ ABC | ABC | f  | f    | f              | f
+ ABC | �bc | t  | t    | t              | t
+ ABC | bbc | t  | t    | t              | t
+ �bc | abc | f  | f    | f              | f
+ �bc | ABC | f  | f    | f              | f
+ �bc | �bc | f  | f    | f              | f
+ �bc | bbc | t  | t    | t              | t
+ bbc | abc | f  | f    | f              | f
+ bbc | ABC | f  | f    | f              | f
+ bbc | �bc | f  | f    | f              | f
+ bbc | bbc | f  | f    | f              | f
+(16 rows)
+
+SELECT a.b AS a, b.b AS b, a.b < b.b COLLATE "C" AS lt,
+       mylt(a.b, b.b COLLATE "C"), mylt_noninline(a.b, b.b COLLATE "C"),
+       mylt_plpgsql(a.b, b.b COLLATE "C")
+FROM collate_test1 a, collate_test1 b
+ORDER BY a.b, b.b;
+  a  |  b  | lt | mylt | mylt_noninline | mylt_plpgsql 
+-----+-----+----+------+----------------+--------------
+ abc | abc | f  | f    | f              | f
+ abc | ABC | f  | f    | f              | f
+ abc | �bc | t  | t    | t              | t
+ abc | bbc | t  | t    | t              | t
+ ABC | abc | t  | t    | t              | t
+ ABC | ABC | f  | f    | f              | f
+ ABC | �bc | t  | t    | t              | t
+ ABC | bbc | t  | t    | t              | t
+ �bc | abc | f  | f    | f              | f
+ �bc | ABC | f  | f    | f              | f
+ �bc | �bc | f  | f    | f              | f
+ �bc | bbc | f  | f    | f              | f
+ bbc | abc | f  | f    | f              | f
+ bbc | ABC | f  | f    | f              | f
+ bbc | �bc | t  | t    | t              | t
+ bbc | bbc | f  | f    | f              | f
+(16 rows)
+
+-- collation override in plpgsql
+CREATE FUNCTION mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+  xx text := x;
+  yy text := y;
+begin
+  return xx < yy;
+end
+$$;
+SELECT mylt2('a', 'B' collate "en_US") as t, mylt2('a', 'B' collate "C") as f;
+ t | f 
+---+---
+ t | f
+(1 row)
+
+CREATE OR REPLACE FUNCTION
+  mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+  xx text COLLATE "POSIX" := x;
+  yy text := y;
+begin
+  return xx < yy;
+end
+$$;
+SELECT mylt2('a', 'B') as f;
+ f 
+---
+ f
+(1 row)
+
+SELECT mylt2('a', 'B' collate "C") as fail; -- conflicting collations
+ERROR:  could not determine which collation to use for string comparison
+HINT:  Use the COLLATE clause to set the collation explicitly.
+CONTEXT:  PL/pgSQL function mylt2(text,text) line 6 at RETURN
+SELECT mylt2('a', 'B' collate "POSIX") as f;
+ f 
+---
+ f
+(1 row)
+
+-- polymorphism
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test1)) ORDER BY 1;
+ unnest 
+--------
+ abc
+ ABC
+ �bc
+ bbc
+(4 rows)
+
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test2)) ORDER BY 1;
+ unnest 
+--------
+ abc
+ ABC
+ bbc
+ �bc
+(4 rows)
+
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test3)) ORDER BY 1;
+ unnest 
+--------
+ ABC
+ abc
+ bbc
+ �bc
+(4 rows)
+
+CREATE FUNCTION dup (anyelement) RETURNS anyelement
+    AS 'select $1' LANGUAGE sql;
+SELECT a, dup(b) FROM collate_test1 ORDER BY 2;
+ a | dup 
+---+-----
+ 1 | abc
+ 4 | ABC
+ 2 | �bc
+ 3 | bbc
+(4 rows)
+
+SELECT a, dup(b) FROM collate_test2 ORDER BY 2;
+ a | dup 
+---+-----
+ 1 | abc
+ 4 | ABC
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+SELECT a, dup(b) FROM collate_test3 ORDER BY 2;
+ a | dup 
+---+-----
+ 4 | ABC
+ 1 | abc
+ 3 | bbc
+ 2 | �bc
+(4 rows)
+
+-- indexes
+CREATE INDEX collate_test1_idx1 ON collate_test1 (b);
+CREATE INDEX collate_test1_idx2 ON collate_test1 (b COLLATE "C");
+CREATE INDEX collate_test1_idx3 ON collate_test1 ((b COLLATE "C")); -- this is different grammatically
+CREATE INDEX collate_test1_idx4 ON collate_test1 (((b||'foo') COLLATE "POSIX"));
+CREATE INDEX collate_test1_idx5 ON collate_test1 (a COLLATE "C"); -- fail
+ERROR:  collations are not supported by type integer
+CREATE INDEX collate_test1_idx6 ON collate_test1 ((a COLLATE "C")); -- fail
+ERROR:  collations are not supported by type integer
+LINE 1: ...ATE INDEX collate_test1_idx6 ON collate_test1 ((a COLLATE "C...
+                                                             ^
+SELECT relname, pg_get_indexdef(oid) FROM pg_class WHERE relname LIKE 'collate_test%_idx%' ORDER BY 1;
+      relname       |                                                  pg_get_indexdef                                                  
+--------------------+-------------------------------------------------------------------------------------------------------------------
+ collate_test1_idx1 | CREATE INDEX collate_test1_idx1 ON collate_tests.collate_test1 USING btree (b)
+ collate_test1_idx2 | CREATE INDEX collate_test1_idx2 ON collate_tests.collate_test1 USING btree (b COLLATE "C")
+ collate_test1_idx3 | CREATE INDEX collate_test1_idx3 ON collate_tests.collate_test1 USING btree (b COLLATE "C")
+ collate_test1_idx4 | CREATE INDEX collate_test1_idx4 ON collate_tests.collate_test1 USING btree (((b || 'foo'::text)) COLLATE "POSIX")
+(4 rows)
+
+-- schema manipulation commands
+CREATE ROLE regress_test_role;
+CREATE SCHEMA test_schema;
+-- We need to do this this way to cope with varying names for encodings:
+do $$
+BEGIN
+  EXECUTE 'CREATE COLLATION test0 (locale = ' ||
+          quote_literal(current_setting('lc_collate')) || ');';
+END
+$$;
+CREATE COLLATION test0 FROM "C"; -- fail, duplicate name
+ERROR:  collation "test0" already exists
+CREATE COLLATION IF NOT EXISTS test0 FROM "C"; -- ok, skipped
+NOTICE:  collation "test0" already exists, skipping
+CREATE COLLATION IF NOT EXISTS test0 (locale = 'foo'); -- ok, skipped
+NOTICE:  collation "test0" for encoding "WIN1252" already exists, skipping
+do $$
+BEGIN
+  EXECUTE 'CREATE COLLATION test1 (lc_collate = ' ||
+          quote_literal(current_setting('lc_collate')) ||
+          ', lc_ctype = ' ||
+          quote_literal(current_setting('lc_ctype')) || ');';
+END
+$$;
+CREATE COLLATION test3 (lc_collate = 'en_US.utf8'); -- fail, need lc_ctype
+ERROR:  parameter "lc_ctype" must be specified
+CREATE COLLATION testx (locale = 'nonsense'); -- fail
+ERROR:  could not create locale "nonsense": No such file or directory
+DETAIL:  The operating system could not find any locale data for the locale name "nonsense".
+CREATE COLLATION test4 FROM nonsense;
+ERROR:  collation "nonsense" for encoding "WIN1252" does not exist
+CREATE COLLATION test5 FROM test0;
+SELECT collname FROM pg_collation WHERE collname LIKE 'test%' ORDER BY 1;
+ collname 
+----------
+ test0
+ test1
+ test5
+(3 rows)
+
+ALTER COLLATION test1 RENAME TO test11;
+ALTER COLLATION test0 RENAME TO test11; -- fail
+ERROR:  collation "test11" for encoding "WIN1252" already exists in schema "collate_tests"
+ALTER COLLATION test1 RENAME TO test22; -- fail
+ERROR:  collation "test1" for encoding "WIN1252" does not exist
+ALTER COLLATION test11 OWNER TO regress_test_role;
+ALTER COLLATION test11 OWNER TO nonsense;
+ERROR:  role "nonsense" does not exist
+ALTER COLLATION test11 SET SCHEMA test_schema;
+COMMENT ON COLLATION test0 IS 'US English';
+SELECT collname, nspname, obj_description(pg_collation.oid, 'pg_collation')
+    FROM pg_collation JOIN pg_namespace ON (collnamespace = pg_namespace.oid)
+    WHERE collname LIKE 'test%'
+    ORDER BY 1;
+ collname |    nspname    | obj_description 
+----------+---------------+-----------------
+ test0    | collate_tests | US English
+ test11   | test_schema   | 
+ test5    | collate_tests | 
+(3 rows)
+
+DROP COLLATION test0, test_schema.test11, test5;
+DROP COLLATION test0; -- fail
+ERROR:  collation "test0" for encoding "WIN1252" does not exist
+DROP COLLATION IF EXISTS test0;
+NOTICE:  collation "test0" does not exist, skipping
+SELECT collname FROM pg_collation WHERE collname LIKE 'test%';
+ collname 
+----------
+(0 rows)
+
+DROP SCHEMA test_schema;
+DROP ROLE regress_test_role;
+-- ALTER
+ALTER COLLATION "en_US" REFRESH VERSION;
+NOTICE:  version has not changed
+-- dependencies
+CREATE COLLATION test0 FROM "C";
+CREATE TABLE collate_dep_test1 (a int, b text COLLATE test0);
+CREATE DOMAIN collate_dep_dom1 AS text COLLATE test0;
+CREATE TYPE collate_dep_test2 AS (x int, y text COLLATE test0);
+CREATE VIEW collate_dep_test3 AS SELECT text 'foo' COLLATE test0 AS foo;
+CREATE TABLE collate_dep_test4t (a int, b text);
+CREATE INDEX collate_dep_test4i ON collate_dep_test4t (b COLLATE test0);
+DROP COLLATION test0 RESTRICT; -- fail
+ERROR:  cannot drop collation test0 because other objects depend on it
+DETAIL:  column b of table collate_dep_test1 depends on collation test0
+type collate_dep_dom1 depends on collation test0
+column y of composite type collate_dep_test2 depends on collation test0
+view collate_dep_test3 depends on collation test0
+index collate_dep_test4i depends on collation test0
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
+DROP COLLATION test0 CASCADE;
+NOTICE:  drop cascades to 5 other objects
+DETAIL:  drop cascades to column b of table collate_dep_test1
+drop cascades to type collate_dep_dom1
+drop cascades to column y of composite type collate_dep_test2
+drop cascades to view collate_dep_test3
+drop cascades to index collate_dep_test4i
+\d collate_dep_test1
+      Table "collate_tests.collate_dep_test1"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ a      | integer |           |          | 
+
+\d collate_dep_test2
+ Composite type "collate_tests.collate_dep_test2"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ x      | integer |           |          | 
+
+DROP TABLE collate_dep_test1, collate_dep_test4t;
+DROP TYPE collate_dep_test2;
+-- test range types and collations
+create type textrange_c as range(subtype=text, collation="C");
+create type textrange_en_us as range(subtype=text, collation="en_US");
+select textrange_c('A','Z') @> 'b'::text;
+ ?column? 
+----------
+ f
+(1 row)
+
+select textrange_en_us('A','Z') @> 'b'::text;
+ ?column? 
+----------
+ t
+(1 row)
+
+drop type textrange_c;
+drop type textrange_en_us;
+-- nondeterministic collations
+-- (not supported with libc provider)
+CREATE COLLATION ctest_det (locale = 'en_US', deterministic = true);
+CREATE COLLATION ctest_nondet (locale = 'en_US', deterministic = false);
+ERROR:  nondeterministic collations not supported with this provider
+-- cleanup
+SET client_min_messages TO warning;
+DROP SCHEMA collate_tests CASCADE;
diff --git a/src/test/regress/expected/collate.windows.win1252_1.out b/src/test/regress/expected/collate.windows.win1252_1.out
new file mode 100644
index 0000000..7bc06ca
--- /dev/null
+++ b/src/test/regress/expected/collate.windows.win1252_1.out
@@ -0,0 +1,13 @@
+/*
+ * This test is meant to run on Windows systems that has successfully run
+ * pg_import_system_collations(). This is possible for builds with a minimum
+ * system version of Windows Vista, and onwards. Also, the database must have
+ * WIN1252 encoding, because of the locales' own encodings. Due to this, some
+ * test are lost from UTF-8 version, like Turkish dotted and undotted 'i'.
+ */
+SELECT getdatabaseencoding() <> 'WIN1252' OR
+       (SELECT count(*) FROM pg_collation WHERE collname IN ('de_DE', 'en_US', 'sv_SE') AND collencoding = pg_char_to_encoding('WIN1252')) <> 3 OR
+       version() !~ 'Visual C\+\+'
+       AS skip_test \gset
+\if :skip_test
+\quit
diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule
index 5b0c73d..7eee69e 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -94,7 +94,7 @@ test: create_table_like alter_generic alter_operator misc async dbsize misc_func
 # rules cannot run concurrently with any test that creates
 # a view or rule in the public schema
 # collate.*.utf8 tests cannot be run in parallel with each other
-test: rules psql psql_crosstab amutils stats_ext collate.linux.utf8
+test: rules psql psql_crosstab amutils stats_ext collate.linux.utf8 collate.windows.win1252
 
 # run by itself so it can run parallel workers
 test: select_parallel
diff --git a/src/test/regress/sql/collate.windows.win1252.sql b/src/test/regress/sql/collate.windows.win1252.sql
new file mode 100644
index 0000000..81314d1
--- /dev/null
+++ b/src/test/regress/sql/collate.windows.win1252.sql
@@ -0,0 +1,419 @@
+/*
+ * This test is meant to run on Windows systems that has successfully run
+ * pg_import_system_collations(). This is possible for builds with a minimum
+ * system version of Windows Vista, and onwards. Also, the database must have
+ * WIN1252 encoding, because of the locales' own encodings. Due to this, some
+ * test are lost from UTF-8 version, like Turkish dotted and undotted 'i'.
+ */
+SELECT getdatabaseencoding() <> 'WIN1252' OR
+       (SELECT count(*) FROM pg_collation WHERE collname IN ('de_DE', 'en_US', 'sv_SE') AND collencoding = pg_char_to_encoding('WIN1252')) <> 3 OR
+       version() !~ 'Visual C\+\+'
+       AS skip_test \gset
+\if :skip_test
+\quit
+\endif
+
+SET client_encoding TO WIN1252;
+
+CREATE SCHEMA collate_tests;
+SET search_path = collate_tests;
+
+
+CREATE TABLE collate_test1 (
+    a int,
+    b text COLLATE "en_US" NOT NULL
+);
+
+\d collate_test1
+
+CREATE TABLE collate_test_fail (
+    a int,
+    b text COLLATE "ja_JP.eucjp"
+);
+
+CREATE TABLE collate_test_fail (
+    a int,
+    b text COLLATE "foo"
+);
+
+CREATE TABLE collate_test_fail (
+    a int COLLATE "en_US",
+    b text
+);
+
+CREATE TABLE collate_test_like (
+    LIKE collate_test1
+);
+
+\d collate_test_like
+
+CREATE TABLE collate_test2 (
+    a int,
+    b text COLLATE "sv_SE"
+);
+
+CREATE TABLE collate_test3 (
+    a int,
+    b text COLLATE "C"
+);
+
+INSERT INTO collate_test1 VALUES (1, 'abc'), (2, '�bc'), (3, 'bbc'), (4, 'ABC');
+INSERT INTO collate_test2 SELECT * FROM collate_test1;
+INSERT INTO collate_test3 SELECT * FROM collate_test1;
+
+SELECT * FROM collate_test1 WHERE b >= 'bbc';
+SELECT * FROM collate_test2 WHERE b >= 'bbc';
+SELECT * FROM collate_test3 WHERE b >= 'bbc';
+SELECT * FROM collate_test3 WHERE b >= 'BBC';
+
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc';
+SELECT * FROM collate_test1 WHERE b >= 'bbc' COLLATE "C";
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "C";
+SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc' COLLATE "en_US";
+
+
+CREATE DOMAIN testdomain_sv AS text COLLATE "sv_SE";
+CREATE DOMAIN testdomain_i AS int COLLATE "sv_SE"; -- fails
+CREATE TABLE collate_test4 (
+    a int,
+    b testdomain_sv
+);
+INSERT INTO collate_test4 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test4 ORDER BY b;
+
+CREATE TABLE collate_test5 (
+    a int,
+    b testdomain_sv COLLATE "en_US"
+);
+INSERT INTO collate_test5 SELECT * FROM collate_test1;
+SELECT a, b FROM collate_test5 ORDER BY b;
+
+
+SELECT a, b FROM collate_test1 ORDER BY b;
+SELECT a, b FROM collate_test2 ORDER BY b;
+SELECT a, b FROM collate_test3 ORDER BY b;
+
+SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+
+-- star expansion
+SELECT * FROM collate_test1 ORDER BY b;
+SELECT * FROM collate_test2 ORDER BY b;
+SELECT * FROM collate_test3 ORDER BY b;
+
+-- constant expression folding
+SELECT 'bbc' COLLATE "en_US" > '�bc' COLLATE "en_US" AS "true";
+SELECT 'bbc' COLLATE "sv_SE" > '�bc' COLLATE "sv_SE" AS "false";
+
+-- LIKE/ILIKE
+
+SELECT * FROM collate_test1 WHERE b LIKE 'abc';
+SELECT * FROM collate_test1 WHERE b LIKE 'abc%';
+SELECT * FROM collate_test1 WHERE b LIKE '%bc%';
+SELECT * FROM collate_test1 WHERE b ILIKE 'abc';
+SELECT * FROM collate_test1 WHERE b ILIKE 'abc%';
+SELECT * FROM collate_test1 WHERE b ILIKE '%bc%';
+
+
+-- The following actually exercises the selectivity estimation for ILIKE.
+SELECT relname FROM pg_class WHERE relname ILIKE 'abc%';
+
+-- regular expressions
+
+SELECT * FROM collate_test1 WHERE b ~ '^abc$';
+SELECT * FROM collate_test1 WHERE b ~ '^abc';
+SELECT * FROM collate_test1 WHERE b ~ 'bc';
+SELECT * FROM collate_test1 WHERE b ~* '^abc$';
+SELECT * FROM collate_test1 WHERE b ~* '^abc';
+SELECT * FROM collate_test1 WHERE b ~* 'bc';
+
+CREATE TABLE collate_test6 (
+    a int,
+    b text COLLATE "en_US"
+);
+INSERT INTO collate_test6 VALUES (1, 'abc'), (2, 'ABC'), (3, '123'), (4, 'ab1'),
+                                 (5, 'a1!'), (6, 'a c'), (7, '!.;'), (8, '   '),
+                                 (9, '�b�'), (10, '�B�');
+SELECT b,
+       b ~ '^[[:alpha:]]+$' AS is_alpha,
+       b ~ '^[[:upper:]]+$' AS is_upper,
+       b ~ '^[[:lower:]]+$' AS is_lower,
+       b ~ '^[[:digit:]]+$' AS is_digit,
+       b ~ '^[[:alnum:]]+$' AS is_alnum,
+       b ~ '^[[:graph:]]+$' AS is_graph,
+       b ~ '^[[:print:]]+$' AS is_print,
+       b ~ '^[[:punct:]]+$' AS is_punct,
+       b ~ '^[[:space:]]+$' AS is_space
+FROM collate_test6;
+
+
+-- The following actually exercises the selectivity estimation for ~*.
+SELECT relname FROM pg_class WHERE relname ~* '^abc';
+
+
+-- to_char
+
+SET lc_time TO 'de_DE';
+SELECT to_char(date '2010-03-01', 'DD TMMON YYYY');
+SELECT to_char(date '2010-03-01', 'DD TMMON YYYY' COLLATE "de_DE");
+
+-- to_date
+
+SELECT to_date('01 M�R 2010', 'DD TMMON YYYY');
+SELECT to_date('01 M�r 2010', 'DD TMMON YYYY');
+SELECT to_date('1234567890ab 2010', 'TMMONTH YYYY'); -- fail
+
+
+-- backwards parsing
+
+CREATE VIEW collview1 AS SELECT * FROM collate_test1 WHERE b COLLATE "C" >= 'bbc';
+CREATE VIEW collview2 AS SELECT a, b FROM collate_test1 ORDER BY b COLLATE "C";
+
+SELECT table_name, view_definition FROM information_schema.views
+  WHERE table_name LIKE 'collview%' ORDER BY 1;
+
+
+-- collation propagation in various expression types
+
+SELECT a, coalesce(b, 'foo') FROM collate_test1 ORDER BY 2;
+SELECT a, coalesce(b, 'foo') FROM collate_test2 ORDER BY 2;
+SELECT a, coalesce(b, 'foo') FROM collate_test3 ORDER BY 2;
+
+SELECT a, b, greatest(b, 'CCC') FROM collate_test1 ORDER BY 3;
+SELECT a, b, greatest(b, 'CCC') FROM collate_test2 ORDER BY 3;
+SELECT a, b, greatest(b, 'CCC') FROM collate_test3 ORDER BY 3;
+
+SELECT a, nullif(b, 'abc') FROM collate_test1 ORDER BY 2;
+SELECT a, nullif(b, 'abc') FROM collate_test2 ORDER BY 2;
+SELECT a, nullif(b, 'abc') FROM collate_test3 ORDER BY 2;
+
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test1 ORDER BY 2;
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test2 ORDER BY 2;
+SELECT a, CASE b WHEN 'abc' THEN 'abcd' ELSE b END FROM collate_test3 ORDER BY 2;
+
+CREATE DOMAIN testdomain AS text;
+SELECT a, b::testdomain FROM collate_test1 ORDER BY 2;
+SELECT a, b::testdomain FROM collate_test2 ORDER BY 2;
+SELECT a, b::testdomain FROM collate_test3 ORDER BY 2;
+SELECT a, b::testdomain_sv FROM collate_test3 ORDER BY 2;
+
+SELECT min(b), max(b) FROM collate_test1;
+SELECT min(b), max(b) FROM collate_test2;
+SELECT min(b), max(b) FROM collate_test3;
+
+SELECT array_agg(b ORDER BY b) FROM collate_test1;
+SELECT array_agg(b ORDER BY b) FROM collate_test2;
+SELECT array_agg(b ORDER BY b) FROM collate_test3;
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test1 ORDER BY 2;
+SELECT a, b FROM collate_test2 UNION SELECT a, b FROM collate_test2 ORDER BY 2;
+SELECT a, b FROM collate_test3 WHERE a < 4 INTERSECT SELECT a, b FROM collate_test3 WHERE a > 1 ORDER BY 2;
+SELECT a, b FROM collate_test3 EXCEPT SELECT a, b FROM collate_test3 WHERE a < 2 ORDER BY 2;
+
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3; -- ok
+SELECT a, b FROM collate_test1 UNION SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+SELECT a, b COLLATE "C" FROM collate_test1 UNION SELECT a, b FROM collate_test3 ORDER BY 2; -- ok
+SELECT a, b FROM collate_test1 INTERSECT SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+SELECT a, b FROM collate_test1 EXCEPT SELECT a, b FROM collate_test3 ORDER BY 2; -- fail
+
+CREATE TABLE test_u AS SELECT a, b FROM collate_test1 UNION ALL SELECT a, b FROM collate_test3; -- fail
+
+-- collation mismatch between recursive and non-recursive term
+WITH RECURSIVE foo(x) AS
+   (SELECT x FROM (VALUES('a' COLLATE "en_US"),('b')) t(x)
+   UNION ALL
+   SELECT (x || 'c') COLLATE "de_DE" FROM foo WHERE length(x) < 10)
+SELECT * FROM foo;
+
+
+-- casting
+
+SELECT CAST('42' AS text COLLATE "C");
+
+SELECT a, CAST(b AS varchar) FROM collate_test1 ORDER BY 2;
+SELECT a, CAST(b AS varchar) FROM collate_test2 ORDER BY 2;
+SELECT a, CAST(b AS varchar) FROM collate_test3 ORDER BY 2;
+
+
+-- propagation of collation in SQL functions (inlined and non-inlined cases)
+-- and plpgsql functions too
+
+CREATE FUNCTION mylt (text, text) RETURNS boolean LANGUAGE sql
+    AS $$ select $1 < $2 $$;
+
+CREATE FUNCTION mylt_noninline (text, text) RETURNS boolean LANGUAGE sql
+    AS $$ select $1 < $2 limit 1 $$;
+
+CREATE FUNCTION mylt_plpgsql (text, text) RETURNS boolean LANGUAGE plpgsql
+    AS $$ begin return $1 < $2; end $$;
+
+SELECT a.b AS a, b.b AS b, a.b < b.b AS lt,
+       mylt(a.b, b.b), mylt_noninline(a.b, b.b), mylt_plpgsql(a.b, b.b)
+FROM collate_test1 a, collate_test1 b
+ORDER BY a.b, b.b;
+
+SELECT a.b AS a, b.b AS b, a.b < b.b COLLATE "C" AS lt,
+       mylt(a.b, b.b COLLATE "C"), mylt_noninline(a.b, b.b COLLATE "C"),
+       mylt_plpgsql(a.b, b.b COLLATE "C")
+FROM collate_test1 a, collate_test1 b
+ORDER BY a.b, b.b;
+
+
+-- collation override in plpgsql
+
+CREATE FUNCTION mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+  xx text := x;
+  yy text := y;
+begin
+  return xx < yy;
+end
+$$;
+
+SELECT mylt2('a', 'B' collate "en_US") as t, mylt2('a', 'B' collate "C") as f;
+
+CREATE OR REPLACE FUNCTION
+  mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+  xx text COLLATE "POSIX" := x;
+  yy text := y;
+begin
+  return xx < yy;
+end
+$$;
+
+SELECT mylt2('a', 'B') as f;
+SELECT mylt2('a', 'B' collate "C") as fail; -- conflicting collations
+SELECT mylt2('a', 'B' collate "POSIX") as f;
+
+
+-- polymorphism
+
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test1)) ORDER BY 1;
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test2)) ORDER BY 1;
+SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test3)) ORDER BY 1;
+
+CREATE FUNCTION dup (anyelement) RETURNS anyelement
+    AS 'select $1' LANGUAGE sql;
+
+SELECT a, dup(b) FROM collate_test1 ORDER BY 2;
+SELECT a, dup(b) FROM collate_test2 ORDER BY 2;
+SELECT a, dup(b) FROM collate_test3 ORDER BY 2;
+
+
+-- indexes
+
+CREATE INDEX collate_test1_idx1 ON collate_test1 (b);
+CREATE INDEX collate_test1_idx2 ON collate_test1 (b COLLATE "C");
+CREATE INDEX collate_test1_idx3 ON collate_test1 ((b COLLATE "C")); -- this is different grammatically
+CREATE INDEX collate_test1_idx4 ON collate_test1 (((b||'foo') COLLATE "POSIX"));
+
+CREATE INDEX collate_test1_idx5 ON collate_test1 (a COLLATE "C"); -- fail
+CREATE INDEX collate_test1_idx6 ON collate_test1 ((a COLLATE "C")); -- fail
+
+SELECT relname, pg_get_indexdef(oid) FROM pg_class WHERE relname LIKE 'collate_test%_idx%' ORDER BY 1;
+
+
+-- schema manipulation commands
+
+CREATE ROLE regress_test_role;
+CREATE SCHEMA test_schema;
+
+-- We need to do this this way to cope with varying names for encodings:
+do $$
+BEGIN
+  EXECUTE 'CREATE COLLATION test0 (locale = ' ||
+          quote_literal(current_setting('lc_collate')) || ');';
+END
+$$;
+CREATE COLLATION test0 FROM "C"; -- fail, duplicate name
+CREATE COLLATION IF NOT EXISTS test0 FROM "C"; -- ok, skipped
+CREATE COLLATION IF NOT EXISTS test0 (locale = 'foo'); -- ok, skipped
+do $$
+BEGIN
+  EXECUTE 'CREATE COLLATION test1 (lc_collate = ' ||
+          quote_literal(current_setting('lc_collate')) ||
+          ', lc_ctype = ' ||
+          quote_literal(current_setting('lc_ctype')) || ');';
+END
+$$;
+CREATE COLLATION test3 (lc_collate = 'en_US.utf8'); -- fail, need lc_ctype
+CREATE COLLATION testx (locale = 'nonsense'); -- fail
+
+CREATE COLLATION test4 FROM nonsense;
+CREATE COLLATION test5 FROM test0;
+
+SELECT collname FROM pg_collation WHERE collname LIKE 'test%' ORDER BY 1;
+
+ALTER COLLATION test1 RENAME TO test11;
+ALTER COLLATION test0 RENAME TO test11; -- fail
+ALTER COLLATION test1 RENAME TO test22; -- fail
+
+ALTER COLLATION test11 OWNER TO regress_test_role;
+ALTER COLLATION test11 OWNER TO nonsense;
+ALTER COLLATION test11 SET SCHEMA test_schema;
+
+COMMENT ON COLLATION test0 IS 'US English';
+
+SELECT collname, nspname, obj_description(pg_collation.oid, 'pg_collation')
+    FROM pg_collation JOIN pg_namespace ON (collnamespace = pg_namespace.oid)
+    WHERE collname LIKE 'test%'
+    ORDER BY 1;
+
+DROP COLLATION test0, test_schema.test11, test5;
+DROP COLLATION test0; -- fail
+DROP COLLATION IF EXISTS test0;
+
+SELECT collname FROM pg_collation WHERE collname LIKE 'test%';
+
+DROP SCHEMA test_schema;
+DROP ROLE regress_test_role;
+
+
+-- ALTER
+
+ALTER COLLATION "en_US" REFRESH VERSION;
+
+
+-- dependencies
+
+CREATE COLLATION test0 FROM "C";
+
+CREATE TABLE collate_dep_test1 (a int, b text COLLATE test0);
+CREATE DOMAIN collate_dep_dom1 AS text COLLATE test0;
+CREATE TYPE collate_dep_test2 AS (x int, y text COLLATE test0);
+CREATE VIEW collate_dep_test3 AS SELECT text 'foo' COLLATE test0 AS foo;
+CREATE TABLE collate_dep_test4t (a int, b text);
+CREATE INDEX collate_dep_test4i ON collate_dep_test4t (b COLLATE test0);
+
+DROP COLLATION test0 RESTRICT; -- fail
+DROP COLLATION test0 CASCADE;
+
+\d collate_dep_test1
+\d collate_dep_test2
+
+DROP TABLE collate_dep_test1, collate_dep_test4t;
+DROP TYPE collate_dep_test2;
+
+-- test range types and collations
+
+create type textrange_c as range(subtype=text, collation="C");
+create type textrange_en_us as range(subtype=text, collation="en_US");
+
+select textrange_c('A','Z') @> 'b'::text;
+select textrange_en_us('A','Z') @> 'b'::text;
+
+drop type textrange_c;
+drop type textrange_en_us;
+
+
+-- nondeterministic collations
+-- (not supported with libc provider)
+
+CREATE COLLATION ctest_det (locale = 'en_US', deterministic = true);
+CREATE COLLATION ctest_nondet (locale = 'en_US', deterministic = false);
+
+
+-- cleanup
+SET client_min_messages TO warning;
+DROP SCHEMA collate_tests CASCADE;
diff --git a/src/tools/msvc/vcregress.pl b/src/tools/msvc/vcregress.pl
index 6dcd742..b6a3951 100644
--- a/src/tools/msvc/vcregress.pl
+++ b/src/tools/msvc/vcregress.pl
@@ -153,6 +153,7 @@ sub installcheck
 sub check
 {
 	my $schedule = shift || 'parallel';
+	my $encoding = $ENV{ENCODING} || "SQL_ASCII";
 	# for backwards compatibility, "serial" runs the tests in
 	# parallel_schedule one by one.
 	my $maxconn = $maxconn;
@@ -167,7 +168,7 @@ sub check
 		"--bindir=",
 		"--schedule=${schedule}_schedule",
 		"--max-concurrent-tests=20",
-		"--encoding=SQL_ASCII",
+		"--encoding=${encoding}",
 		"--no-locale",
 		"--temp-instance=./tmp_check");
 	push(@args, $maxconn)     if $maxconn;
-- 
2.11.0