From 29923859f91f94c97417b8417ff8475cf4261be1 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Sun, 24 Sep 2017 00:56:31 -0400
Subject: [PATCH] Allow ICU to use SortSupport on Windows with UTF-8
There is no reason to ever prevent the use of SortSupport on Windows
when ICU locales are used. We previously avoided SortSupport on Windows
with UTF-8 server encoding and a non C-locale due to restrictions in
Windows' libc functionality.
This is now considered to be a restriction in one platform's libc
collation provider, and not a more general platform restriction.
Reported-by: Peter Geoghegan <pg@bowt.ie>
---
src/backend/utils/adt/varlena.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index ebfb823fb8c..b16f3d48a10 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -1823,12 +1823,6 @@ varstr_sortsupport(SortSupport ssup, Oid collid, bool bpchar)
* requirements of BpChar callers. However, if LC_COLLATE = C, we can
* make things quite a bit faster with varstrfastcmp_c or bpcharfastcmp_c,
* both of which use memcmp() rather than strcoll().
- *
- * There is a further exception on Windows. When the database encoding is
- * UTF-8 and we are not using the C collation, complex hacks are required.
- * We don't currently have a comparator that handles that case, so we fall
- * back on the slow method of having the sort code invoke bttextcmp() (in
- * the case of text) via the fmgr trampoline.
*/
if (lc_collate_is_c(collid))
{
@@ -1839,14 +1833,8 @@ varstr_sortsupport(SortSupport ssup, Oid collid, bool bpchar)
collate_c = true;
}
-#ifdef WIN32
- else if (GetDatabaseEncoding() == PG_UTF8)
- return;
-#endif
else
{
- ssup->comparator = varstrfastcmp_locale;
-
/*
* We need a collation-sensitive comparison. To make things faster,
* we'll figure out the collation based on the locale id and cache the
@@ -1867,6 +1855,22 @@ varstr_sortsupport(SortSupport ssup, Oid collid, bool bpchar)
}
locale = pg_newlocale_from_collation(collid);
}
+
+ /*
+ * There is a further exception on Windows. When the database
+ * encoding is UTF-8 and we are not using the C collation, complex
+ * hacks are required. We don't currently have a comparator that
+ * handles that case, so we fall back on the slow method of having the
+ * sort code invoke bttextcmp() (in the case of text) via the fmgr
+ * trampoline. ICU locales work just the same on Windows, however.
+ */
+#ifdef WIN32
+ if (GetDatabaseEncoding() == PG_UTF8 &&
+ !(locale && locale->provider == COLLPROVIDER_ICU))
+ return;
+#endif
+
+ ssup->comparator = varstrfastcmp_locale;
}
/*
--
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