Refactor to introduce pg_strcoll().
Started by Jeff Davisover 3 years ago7 messages
Refactors to isolate strcoll, wcscoll, and ucol_strcoll into
pg_locale.c which seems like a better place. Most of the buffer
manipulation and equality optimizations are still left in varlena.c.
Patch attached.
I'm not able to easily test on windows, but it should be close to
correct as I just moved some code around.
Is there a good way to look for regressions (perf or correctness) when
making changes in this area, especially on windows and/or with strange
collation rules? What I did doesn't look like a problem, but there's
always a chance of a regression.
--
Jeff Davis
PostgreSQL Contributor Team - AWS
Attachments:
0001-Refactor-introduce-pg_strcoll.patchtext/x-patch; charset=UTF-8; name=0001-Refactor-introduce-pg_strcoll.patchDownload
From 644ee9ac28652884d91f17f4fc7755104538d9f1 Mon Sep 17 00:00:00 2001
From: Jeff Davis <jeff@j-davis.com>
Date: Thu, 6 Oct 2022 10:46:36 -0700
Subject: [PATCH] Refactor: introduce pg_strcoll().
Isolate collation routines into pg_locale.c and simplify varlena.c.
---
src/backend/utils/adt/pg_locale.c | 178 +++++++++++++++++++++++++
src/backend/utils/adt/varlena.c | 207 +-----------------------------
src/include/utils/pg_locale.h | 3 +-
3 files changed, 182 insertions(+), 206 deletions(-)
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 2b42d9ccd8..696ff75201 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -1639,6 +1639,184 @@ pg_newlocale_from_collation(Oid collid)
return cache_entry->locale;
}
+/*
+ * win32_utf8_wcscoll
+ *
+ * Convert UTF8 arguments to wide characters and invoke wcscoll() or
+ * wcscoll_l(). Will allocate on large input.
+ */
+#ifdef WIN32
+#define TEXTBUFLEN 1024
+static int
+win32_utf8_wcscoll(const char *arg1, int len1, const char *arg2, int len2,
+ pg_locale_t locale)
+{
+ char a1buf[TEXTBUFLEN];
+ char a2buf[TEXTBUFLEN];
+ char *a1p,
+ *a2p;
+ int a1len;
+ int a2len;
+ int r;
+ int result;
+
+ if (len1 >= TEXTBUFLEN / 2)
+ {
+ a1len = len1 * 2 + 2;
+ a1p = palloc(a1len);
+ }
+ else
+ {
+ a1len = TEXTBUFLEN;
+ a1p = a1buf;
+ }
+ if (len2 >= TEXTBUFLEN / 2)
+ {
+ a2len = len2 * 2 + 2;
+ a2p = palloc(a2len);
+ }
+ else
+ {
+ a2len = TEXTBUFLEN;
+ a2p = a2buf;
+ }
+
+ /* API does not work for zero-length input */
+ if (len1 == 0)
+ r = 0;
+ else
+ {
+ r = MultiByteToWideChar(CP_UTF8, 0, arg1, len1,
+ (LPWSTR) a1p, a1len / 2);
+ if (!r)
+ ereport(ERROR,
+ (errmsg("could not convert string to UTF-16: error code %lu",
+ GetLastError())));
+ }
+ ((LPWSTR) a1p)[r] = 0;
+
+ if (len2 == 0)
+ r = 0;
+ else
+ {
+ r = MultiByteToWideChar(CP_UTF8, 0, arg2, len2,
+ (LPWSTR) a2p, a2len / 2);
+ if (!r)
+ ereport(ERROR,
+ (errmsg("could not convert string to UTF-16: error code %lu",
+ GetLastError())));
+ }
+ ((LPWSTR) a2p)[r] = 0;
+
+ errno = 0;
+#ifdef HAVE_LOCALE_T
+ if (locale)
+ result = wcscoll_l((LPWSTR) a1p, (LPWSTR) a2p, locale->info.lt);
+ else
+#endif
+ result = wcscoll((LPWSTR) a1p, (LPWSTR) a2p);
+ if (result == 2147483647) /* _NLSCMPERROR; missing from mingw
+ * headers */
+ ereport(ERROR,
+ (errmsg("could not compare Unicode strings: %m")));
+
+ if (a1p != a1buf)
+ pfree(a1p);
+ if (a2p != a2buf)
+ pfree(a2p);
+
+ return result;
+}
+#endif
+
+/*
+ * pg_strcoll
+ *
+ * Call ucol_strcollUTF8(), ucol_strcoll(), strcoll(), strcoll_l(), wcscoll(),
+ * or wcscoll_l() as appropriate for the given locale, platform, and database
+ * encoding. Arguments must be NUL-terminated. If the locale is not specified,
+ * use the database collation.
+ *
+ * If the collation is deterministic, break ties with memcmp(), and then with
+ * the string length.
+ */
+int
+pg_strcoll(const char *arg1, int len1, const char *arg2, int len2,
+ pg_locale_t locale)
+{
+ int result;
+
+#ifdef WIN32
+ /* Win32 does not have UTF-8, so we need to map to UTF-16 */
+ if (GetDatabaseEncoding() == PG_UTF8
+ && (!locale || locale->provider == COLLPROVIDER_LIBC))
+ {
+ result = win32_utf8_wcscoll(arg1, len1, arg2, len2, locale);
+ }
+ else
+#endif /* WIN32 */
+ if (locale)
+ {
+ if (locale->provider == COLLPROVIDER_ICU)
+ {
+#ifdef USE_ICU
+#ifdef HAVE_UCOL_STRCOLLUTF8
+ if (GetDatabaseEncoding() == PG_UTF8)
+ {
+ UErrorCode status;
+
+ status = U_ZERO_ERROR;
+ result = ucol_strcollUTF8(locale->info.icu.ucol,
+ arg1, len1,
+ arg2, len2,
+ &status);
+ if (U_FAILURE(status))
+ ereport(ERROR,
+ (errmsg("collation failed: %s", u_errorName(status))));
+ }
+ else
+#endif
+ {
+ int32_t ulen1,
+ ulen2;
+ UChar *uchar1,
+ *uchar2;
+
+ ulen1 = icu_to_uchar(&uchar1, arg1, len1);
+ ulen2 = icu_to_uchar(&uchar2, arg2, len2);
+
+ result = ucol_strcoll(locale->info.icu.ucol,
+ uchar1, ulen1,
+ uchar2, ulen2);
+
+ pfree(uchar1);
+ pfree(uchar2);
+ }
+#else /* not USE_ICU */
+ /* shouldn't happen */
+ elog(ERROR, "unsupported collprovider: %c", locale->provider);
+#endif /* not USE_ICU */
+ }
+ else
+ {
+#ifdef HAVE_LOCALE_T
+ result = strcoll_l(arg1, arg2, locale->info.lt);
+#else
+ /* shouldn't happen */
+ elog(ERROR, "unsupported collprovider: %c", locale->provider);
+#endif
+ }
+ }
+ else
+ result = strcoll(arg1, arg2);
+
+ /* Break tie if necessary. */
+ if (result == 0 && (!locale || locale->deterministic))
+ result = strcmp(arg1, arg2);
+
+ return result;
+}
+
/*
* Get provider-specific collation version string for the given collation from
* the operating system/library.
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 1f6e090821..5be7eaee9f 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -1555,93 +1555,6 @@ varstr_cmp(const char *arg1, int len1, const char *arg2, int len2, Oid collid)
if (len1 == len2 && memcmp(arg1, arg2, len1) == 0)
return 0;
-#ifdef WIN32
- /* Win32 does not have UTF-8, so we need to map to UTF-16 */
- if (GetDatabaseEncoding() == PG_UTF8
- && (!mylocale || mylocale->provider == COLLPROVIDER_LIBC))
- {
- int a1len;
- int a2len;
- int r;
-
- if (len1 >= TEXTBUFLEN / 2)
- {
- a1len = len1 * 2 + 2;
- a1p = palloc(a1len);
- }
- else
- {
- a1len = TEXTBUFLEN;
- a1p = a1buf;
- }
- if (len2 >= TEXTBUFLEN / 2)
- {
- a2len = len2 * 2 + 2;
- a2p = palloc(a2len);
- }
- else
- {
- a2len = TEXTBUFLEN;
- a2p = a2buf;
- }
-
- /* stupid Microsloth API does not work for zero-length input */
- if (len1 == 0)
- r = 0;
- else
- {
- r = MultiByteToWideChar(CP_UTF8, 0, arg1, len1,
- (LPWSTR) a1p, a1len / 2);
- if (!r)
- ereport(ERROR,
- (errmsg("could not convert string to UTF-16: error code %lu",
- GetLastError())));
- }
- ((LPWSTR) a1p)[r] = 0;
-
- if (len2 == 0)
- r = 0;
- else
- {
- r = MultiByteToWideChar(CP_UTF8, 0, arg2, len2,
- (LPWSTR) a2p, a2len / 2);
- if (!r)
- ereport(ERROR,
- (errmsg("could not convert string to UTF-16: error code %lu",
- GetLastError())));
- }
- ((LPWSTR) a2p)[r] = 0;
-
- errno = 0;
-#ifdef HAVE_LOCALE_T
- if (mylocale)
- result = wcscoll_l((LPWSTR) a1p, (LPWSTR) a2p, mylocale->info.lt);
- else
-#endif
- result = wcscoll((LPWSTR) a1p, (LPWSTR) a2p);
- if (result == 2147483647) /* _NLSCMPERROR; missing from mingw
- * headers */
- ereport(ERROR,
- (errmsg("could not compare Unicode strings: %m")));
-
- /* Break tie if necessary. */
- if (result == 0 &&
- (!mylocale || mylocale->deterministic))
- {
- result = memcmp(arg1, arg2, Min(len1, len2));
- if ((result == 0) && (len1 != len2))
- result = (len1 < len2) ? -1 : 1;
- }
-
- if (a1p != a1buf)
- pfree(a1p);
- if (a2p != a2buf)
- pfree(a2p);
-
- return result;
- }
-#endif /* WIN32 */
-
if (len1 >= TEXTBUFLEN)
a1p = (char *) palloc(len1 + 1);
else
@@ -1656,65 +1569,7 @@ varstr_cmp(const char *arg1, int len1, const char *arg2, int len2, Oid collid)
memcpy(a2p, arg2, len2);
a2p[len2] = '\0';
- if (mylocale)
- {
- if (mylocale->provider == COLLPROVIDER_ICU)
- {
-#ifdef USE_ICU
-#ifdef HAVE_UCOL_STRCOLLUTF8
- if (GetDatabaseEncoding() == PG_UTF8)
- {
- UErrorCode status;
-
- status = U_ZERO_ERROR;
- result = ucol_strcollUTF8(mylocale->info.icu.ucol,
- arg1, len1,
- arg2, len2,
- &status);
- if (U_FAILURE(status))
- ereport(ERROR,
- (errmsg("collation failed: %s", u_errorName(status))));
- }
- else
-#endif
- {
- int32_t ulen1,
- ulen2;
- UChar *uchar1,
- *uchar2;
-
- ulen1 = icu_to_uchar(&uchar1, arg1, len1);
- ulen2 = icu_to_uchar(&uchar2, arg2, len2);
-
- result = ucol_strcoll(mylocale->info.icu.ucol,
- uchar1, ulen1,
- uchar2, ulen2);
-
- pfree(uchar1);
- pfree(uchar2);
- }
-#else /* not USE_ICU */
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", mylocale->provider);
-#endif /* not USE_ICU */
- }
- else
- {
-#ifdef HAVE_LOCALE_T
- result = strcoll_l(a1p, a2p, mylocale->info.lt);
-#else
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", mylocale->provider);
-#endif
- }
- }
- else
- result = strcoll(a1p, a2p);
-
- /* Break tie if necessary. */
- if (result == 0 &&
- (!mylocale || mylocale->deterministic))
- result = strcmp(a1p, a2p);
+ result = pg_strcoll(a1p, len1, a2p, len2, mylocale);
if (a1p != a1buf)
pfree(a1p);
@@ -2377,65 +2232,7 @@ varstrfastcmp_locale(char *a1p, int len1, char *a2p, int len2, SortSupport ssup)
return sss->last_returned;
}
- if (sss->locale)
- {
- if (sss->locale->provider == COLLPROVIDER_ICU)
- {
-#ifdef USE_ICU
-#ifdef HAVE_UCOL_STRCOLLUTF8
- if (GetDatabaseEncoding() == PG_UTF8)
- {
- UErrorCode status;
-
- status = U_ZERO_ERROR;
- result = ucol_strcollUTF8(sss->locale->info.icu.ucol,
- a1p, len1,
- a2p, len2,
- &status);
- if (U_FAILURE(status))
- ereport(ERROR,
- (errmsg("collation failed: %s", u_errorName(status))));
- }
- else
-#endif
- {
- int32_t ulen1,
- ulen2;
- UChar *uchar1,
- *uchar2;
-
- ulen1 = icu_to_uchar(&uchar1, a1p, len1);
- ulen2 = icu_to_uchar(&uchar2, a2p, len2);
-
- result = ucol_strcoll(sss->locale->info.icu.ucol,
- uchar1, ulen1,
- uchar2, ulen2);
-
- pfree(uchar1);
- pfree(uchar2);
- }
-#else /* not USE_ICU */
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", sss->locale->provider);
-#endif /* not USE_ICU */
- }
- else
- {
-#ifdef HAVE_LOCALE_T
- result = strcoll_l(sss->buf1, sss->buf2, sss->locale->info.lt);
-#else
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", sss->locale->provider);
-#endif
- }
- }
- else
- result = strcoll(sss->buf1, sss->buf2);
-
- /* Break tie if necessary. */
- if (result == 0 &&
- (!sss->locale || sss->locale->deterministic))
- result = strcmp(sss->buf1, sss->buf2);
+ result = pg_strcoll(sss->buf1, len1, sss->buf2, len2, sss->locale);
/* Cache result, perhaps saving an expensive strcoll() call next time */
sss->cache_blob = false;
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index a875942123..d75b16a27f 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -98,7 +98,8 @@ extern void make_icu_collator(const char *iculocstr,
struct pg_locale_struct *resultp);
extern pg_locale_t pg_newlocale_from_collation(Oid collid);
-
+extern int pg_strcoll(const char *arg1, int len1, const char *arg2, int len2,
+ pg_locale_t locale);
extern char *get_collation_actual_version(char collprovider, const char *collcollate);
#ifdef USE_ICU
--
2.34.1
Re: Refactor to introduce pg_strcoll().
On 07.10.22 01:15, Jeff Davis wrote:
+ * Call ucol_strcollUTF8(), ucol_strcoll(), strcoll(), strcoll_l(), wcscoll(), + * or wcscoll_l() as appropriate for the given locale, platform, and database + * encoding. Arguments must be NUL-terminated. If the locale is not specified, + * use the database collation. + * + * If the collation is deterministic, break ties with memcmp(), and then with + * the string length. + */ +int +pg_strcoll(const char *arg1, int len1, const char *arg2, int len2, + pg_locale_t locale)
It's a bit confusing that arguments must be NUL-terminated, but the
length is still specified. Maybe another sentence to explain that would
be helpful.
The length arguments ought to be of type size_t, I think.
Re: Refactor to introduce pg_strcoll().
On Thu, 2022-10-13 at 10:57 +0200, Peter Eisentraut wrote:
It's a bit confusing that arguments must be NUL-terminated, but the
length is still specified. Maybe another sentence to explain that
would
be helpful.
Added a comment. It was a little frustrating to get a perfectly clean
API, because the callers do some buffer manipulation and optimizations
of their own. I think this is an improvement, but suggestions welcome.
If win32 is used with UTF-8 and wcscoll, it ends up allocating some
extra stack space for the temporary buffers, whereas previously it used
the buffers on the stack of varstr_cmp(). I'm not sure if that's a
problem or not.
The length arguments ought to be of type size_t, I think.
Changed.
Thank you.
--
Jeff Davis
PostgreSQL Contributor Team - AWS
Attachments:
v2-0001-Refactor-introduce-pg_strcoll.patchtext/x-patch; charset=UTF-8; name=v2-0001-Refactor-introduce-pg_strcoll.patchDownload
From 4d5664552a8a86418a94c37fd4ab8ca3a665c1cd Mon Sep 17 00:00:00 2001
From: Jeff Davis <jeff@j-davis.com>
Date: Thu, 6 Oct 2022 10:46:36 -0700
Subject: [PATCH] Refactor: introduce pg_strcoll().
Isolate collation routines into pg_locale.c and simplify varlena.c.
---
src/backend/utils/adt/pg_locale.c | 180 ++++++++++++++++++++++++++
src/backend/utils/adt/varlena.c | 207 +-----------------------------
src/include/utils/pg_locale.h | 3 +-
3 files changed, 184 insertions(+), 206 deletions(-)
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 2b42d9ccd8..3eb6a67bdc 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -1639,6 +1639,186 @@ pg_newlocale_from_collation(Oid collid)
return cache_entry->locale;
}
+/*
+ * win32_utf8_wcscoll
+ *
+ * Convert UTF8 arguments to wide characters and invoke wcscoll() or
+ * wcscoll_l(). Will allocate on large input.
+ */
+#ifdef WIN32
+#define TEXTBUFLEN 1024
+static int
+win32_utf8_wcscoll(const char *arg1, size_t len1, const char *arg2,
+ size_t len2, pg_locale_t locale)
+{
+ char a1buf[TEXTBUFLEN];
+ char a2buf[TEXTBUFLEN];
+ char *a1p,
+ *a2p;
+ int a1len;
+ int a2len;
+ int r;
+ int result;
+
+ if (len1 >= TEXTBUFLEN / 2)
+ {
+ a1len = len1 * 2 + 2;
+ a1p = palloc(a1len);
+ }
+ else
+ {
+ a1len = TEXTBUFLEN;
+ a1p = a1buf;
+ }
+ if (len2 >= TEXTBUFLEN / 2)
+ {
+ a2len = len2 * 2 + 2;
+ a2p = palloc(a2len);
+ }
+ else
+ {
+ a2len = TEXTBUFLEN;
+ a2p = a2buf;
+ }
+
+ /* API does not work for zero-length input */
+ if (len1 == 0)
+ r = 0;
+ else
+ {
+ r = MultiByteToWideChar(CP_UTF8, 0, arg1, len1,
+ (LPWSTR) a1p, a1len / 2);
+ if (!r)
+ ereport(ERROR,
+ (errmsg("could not convert string to UTF-16: error code %lu",
+ GetLastError())));
+ }
+ ((LPWSTR) a1p)[r] = 0;
+
+ if (len2 == 0)
+ r = 0;
+ else
+ {
+ r = MultiByteToWideChar(CP_UTF8, 0, arg2, len2,
+ (LPWSTR) a2p, a2len / 2);
+ if (!r)
+ ereport(ERROR,
+ (errmsg("could not convert string to UTF-16: error code %lu",
+ GetLastError())));
+ }
+ ((LPWSTR) a2p)[r] = 0;
+
+ errno = 0;
+#ifdef HAVE_LOCALE_T
+ if (locale)
+ result = wcscoll_l((LPWSTR) a1p, (LPWSTR) a2p, locale->info.lt);
+ else
+#endif
+ result = wcscoll((LPWSTR) a1p, (LPWSTR) a2p);
+ if (result == 2147483647) /* _NLSCMPERROR; missing from mingw
+ * headers */
+ ereport(ERROR,
+ (errmsg("could not compare Unicode strings: %m")));
+
+ if (a1p != a1buf)
+ pfree(a1p);
+ if (a2p != a2buf)
+ pfree(a2p);
+
+ return result;
+}
+#endif
+
+/*
+ * pg_strcoll
+ *
+ * Call ucol_strcollUTF8(), ucol_strcoll(), strcoll(), strcoll_l(), wcscoll(),
+ * or wcscoll_l() as appropriate for the given locale, platform, and database
+ * encoding. If the locale is not specified, use the database collation.
+ *
+ * Arguments must be NUL-terminated so they can be passed directly to
+ * strcoll(); but we also need the lengths to pass to ucol_strcoll().
+ *
+ * If the collation is deterministic, break ties with memcmp(), and then with
+ * the string length.
+ */
+int
+pg_strcoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
+ pg_locale_t locale)
+{
+ int result;
+
+#ifdef WIN32
+ /* Win32 does not have UTF-8, so we need to map to UTF-16 */
+ if (GetDatabaseEncoding() == PG_UTF8
+ && (!locale || locale->provider == COLLPROVIDER_LIBC))
+ {
+ result = win32_utf8_wcscoll(arg1, len1, arg2, len2, locale);
+ }
+ else
+#endif /* WIN32 */
+ if (locale)
+ {
+ if (locale->provider == COLLPROVIDER_ICU)
+ {
+#ifdef USE_ICU
+#ifdef HAVE_UCOL_STRCOLLUTF8
+ if (GetDatabaseEncoding() == PG_UTF8)
+ {
+ UErrorCode status;
+
+ status = U_ZERO_ERROR;
+ result = ucol_strcollUTF8(locale->info.icu.ucol,
+ arg1, len1,
+ arg2, len2,
+ &status);
+ if (U_FAILURE(status))
+ ereport(ERROR,
+ (errmsg("collation failed: %s", u_errorName(status))));
+ }
+ else
+#endif
+ {
+ int32_t ulen1,
+ ulen2;
+ UChar *uchar1,
+ *uchar2;
+
+ ulen1 = icu_to_uchar(&uchar1, arg1, len1);
+ ulen2 = icu_to_uchar(&uchar2, arg2, len2);
+
+ result = ucol_strcoll(locale->info.icu.ucol,
+ uchar1, ulen1,
+ uchar2, ulen2);
+
+ pfree(uchar1);
+ pfree(uchar2);
+ }
+#else /* not USE_ICU */
+ /* shouldn't happen */
+ elog(ERROR, "unsupported collprovider: %c", locale->provider);
+#endif /* not USE_ICU */
+ }
+ else
+ {
+#ifdef HAVE_LOCALE_T
+ result = strcoll_l(arg1, arg2, locale->info.lt);
+#else
+ /* shouldn't happen */
+ elog(ERROR, "unsupported collprovider: %c", locale->provider);
+#endif
+ }
+ }
+ else
+ result = strcoll(arg1, arg2);
+
+ /* Break tie if necessary. */
+ if (result == 0 && (!locale || locale->deterministic))
+ result = strcmp(arg1, arg2);
+
+ return result;
+}
+
/*
* Get provider-specific collation version string for the given collation from
* the operating system/library.
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 1f6e090821..5be7eaee9f 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -1555,93 +1555,6 @@ varstr_cmp(const char *arg1, int len1, const char *arg2, int len2, Oid collid)
if (len1 == len2 && memcmp(arg1, arg2, len1) == 0)
return 0;
-#ifdef WIN32
- /* Win32 does not have UTF-8, so we need to map to UTF-16 */
- if (GetDatabaseEncoding() == PG_UTF8
- && (!mylocale || mylocale->provider == COLLPROVIDER_LIBC))
- {
- int a1len;
- int a2len;
- int r;
-
- if (len1 >= TEXTBUFLEN / 2)
- {
- a1len = len1 * 2 + 2;
- a1p = palloc(a1len);
- }
- else
- {
- a1len = TEXTBUFLEN;
- a1p = a1buf;
- }
- if (len2 >= TEXTBUFLEN / 2)
- {
- a2len = len2 * 2 + 2;
- a2p = palloc(a2len);
- }
- else
- {
- a2len = TEXTBUFLEN;
- a2p = a2buf;
- }
-
- /* stupid Microsloth API does not work for zero-length input */
- if (len1 == 0)
- r = 0;
- else
- {
- r = MultiByteToWideChar(CP_UTF8, 0, arg1, len1,
- (LPWSTR) a1p, a1len / 2);
- if (!r)
- ereport(ERROR,
- (errmsg("could not convert string to UTF-16: error code %lu",
- GetLastError())));
- }
- ((LPWSTR) a1p)[r] = 0;
-
- if (len2 == 0)
- r = 0;
- else
- {
- r = MultiByteToWideChar(CP_UTF8, 0, arg2, len2,
- (LPWSTR) a2p, a2len / 2);
- if (!r)
- ereport(ERROR,
- (errmsg("could not convert string to UTF-16: error code %lu",
- GetLastError())));
- }
- ((LPWSTR) a2p)[r] = 0;
-
- errno = 0;
-#ifdef HAVE_LOCALE_T
- if (mylocale)
- result = wcscoll_l((LPWSTR) a1p, (LPWSTR) a2p, mylocale->info.lt);
- else
-#endif
- result = wcscoll((LPWSTR) a1p, (LPWSTR) a2p);
- if (result == 2147483647) /* _NLSCMPERROR; missing from mingw
- * headers */
- ereport(ERROR,
- (errmsg("could not compare Unicode strings: %m")));
-
- /* Break tie if necessary. */
- if (result == 0 &&
- (!mylocale || mylocale->deterministic))
- {
- result = memcmp(arg1, arg2, Min(len1, len2));
- if ((result == 0) && (len1 != len2))
- result = (len1 < len2) ? -1 : 1;
- }
-
- if (a1p != a1buf)
- pfree(a1p);
- if (a2p != a2buf)
- pfree(a2p);
-
- return result;
- }
-#endif /* WIN32 */
-
if (len1 >= TEXTBUFLEN)
a1p = (char *) palloc(len1 + 1);
else
@@ -1656,65 +1569,7 @@ varstr_cmp(const char *arg1, int len1, const char *arg2, int len2, Oid collid)
memcpy(a2p, arg2, len2);
a2p[len2] = '\0';
- if (mylocale)
- {
- if (mylocale->provider == COLLPROVIDER_ICU)
- {
-#ifdef USE_ICU
-#ifdef HAVE_UCOL_STRCOLLUTF8
- if (GetDatabaseEncoding() == PG_UTF8)
- {
- UErrorCode status;
-
- status = U_ZERO_ERROR;
- result = ucol_strcollUTF8(mylocale->info.icu.ucol,
- arg1, len1,
- arg2, len2,
- &status);
- if (U_FAILURE(status))
- ereport(ERROR,
- (errmsg("collation failed: %s", u_errorName(status))));
- }
- else
-#endif
- {
- int32_t ulen1,
- ulen2;
- UChar *uchar1,
- *uchar2;
-
- ulen1 = icu_to_uchar(&uchar1, arg1, len1);
- ulen2 = icu_to_uchar(&uchar2, arg2, len2);
-
- result = ucol_strcoll(mylocale->info.icu.ucol,
- uchar1, ulen1,
- uchar2, ulen2);
-
- pfree(uchar1);
- pfree(uchar2);
- }
-#else /* not USE_ICU */
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", mylocale->provider);
-#endif /* not USE_ICU */
- }
- else
- {
-#ifdef HAVE_LOCALE_T
- result = strcoll_l(a1p, a2p, mylocale->info.lt);
-#else
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", mylocale->provider);
-#endif
- }
- }
- else
- result = strcoll(a1p, a2p);
-
- /* Break tie if necessary. */
- if (result == 0 &&
- (!mylocale || mylocale->deterministic))
- result = strcmp(a1p, a2p);
+ result = pg_strcoll(a1p, len1, a2p, len2, mylocale);
if (a1p != a1buf)
pfree(a1p);
@@ -2377,65 +2232,7 @@ varstrfastcmp_locale(char *a1p, int len1, char *a2p, int len2, SortSupport ssup)
return sss->last_returned;
}
- if (sss->locale)
- {
- if (sss->locale->provider == COLLPROVIDER_ICU)
- {
-#ifdef USE_ICU
-#ifdef HAVE_UCOL_STRCOLLUTF8
- if (GetDatabaseEncoding() == PG_UTF8)
- {
- UErrorCode status;
-
- status = U_ZERO_ERROR;
- result = ucol_strcollUTF8(sss->locale->info.icu.ucol,
- a1p, len1,
- a2p, len2,
- &status);
- if (U_FAILURE(status))
- ereport(ERROR,
- (errmsg("collation failed: %s", u_errorName(status))));
- }
- else
-#endif
- {
- int32_t ulen1,
- ulen2;
- UChar *uchar1,
- *uchar2;
-
- ulen1 = icu_to_uchar(&uchar1, a1p, len1);
- ulen2 = icu_to_uchar(&uchar2, a2p, len2);
-
- result = ucol_strcoll(sss->locale->info.icu.ucol,
- uchar1, ulen1,
- uchar2, ulen2);
-
- pfree(uchar1);
- pfree(uchar2);
- }
-#else /* not USE_ICU */
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", sss->locale->provider);
-#endif /* not USE_ICU */
- }
- else
- {
-#ifdef HAVE_LOCALE_T
- result = strcoll_l(sss->buf1, sss->buf2, sss->locale->info.lt);
-#else
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", sss->locale->provider);
-#endif
- }
- }
- else
- result = strcoll(sss->buf1, sss->buf2);
-
- /* Break tie if necessary. */
- if (result == 0 &&
- (!sss->locale || sss->locale->deterministic))
- result = strcmp(sss->buf1, sss->buf2);
+ result = pg_strcoll(sss->buf1, len1, sss->buf2, len2, sss->locale);
/* Cache result, perhaps saving an expensive strcoll() call next time */
sss->cache_blob = false;
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index a875942123..59a4c9ad0d 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -98,7 +98,8 @@ extern void make_icu_collator(const char *iculocstr,
struct pg_locale_struct *resultp);
extern pg_locale_t pg_newlocale_from_collation(Oid collid);
-
+extern int pg_strcoll(const char *arg1, size_t len1, const char *arg2,
+ size_t len2, pg_locale_t locale);
extern char *get_collation_actual_version(char collprovider, const char *collcollate);
#ifdef USE_ICU
--
2.34.1
Re: Refactor to introduce pg_strcoll().
On 15.10.22 01:00, Jeff Davis wrote:
On Thu, 2022-10-13 at 10:57 +0200, Peter Eisentraut wrote:
It's a bit confusing that arguments must be NUL-terminated, but the
length is still specified. Maybe another sentence to explain that
would
be helpful.Added a comment. It was a little frustrating to get a perfectly clean
API, because the callers do some buffer manipulation and optimizations
of their own. I think this is an improvement, but suggestions welcome.If win32 is used with UTF-8 and wcscoll, it ends up allocating some
extra stack space for the temporary buffers, whereas previously it used
the buffers on the stack of varstr_cmp(). I'm not sure if that's a
problem or not.
Refactoring the common code from varstr_cmp() and varstrfastcmp_locale()
looks like a clear win.
But I think putting the Windows UTF-8 code (win32_utf8_wcscoll()) from
varstr_cmp() into pg_strcoll() might create future complications.
Normally, it would be up to varstr_sortsupport() to set up a
Windows/UTF-8 specific comparator function, but it says there it's not
implemented. But someone who wanted to implement that would have to
lift it back out of pg_strcoll, or rearrange the code in some other way.
It's not a clear win, I think. Perhaps you have some follow-up work
planned, in which case it might be better to consider this in more
context. Otherwise, I'd be tempted to leave it where it was in
varstr_cmp(). (It could still be a separate function, to keep
varstr_cmp() itself a bit smaller.)
Re: Refactor to introduce pg_strcoll().
On Tue, 2022-11-01 at 13:36 +0100, Peter Eisentraut wrote:
But I think putting the Windows UTF-8 code (win32_utf8_wcscoll())
from
varstr_cmp() into pg_strcoll() might create future complications.
Normally, it would be up to varstr_sortsupport() to set up a
Windows/UTF-8 specific comparator function, but it says there it's
not
implemented. But someone who wanted to implement that would have to
lift it back out of pg_strcoll, or rearrange the code in some other
way.
Is there a reason that it wouldn't work to just use
varlenafastcmp_locale() after my patch? The comment says:
/*
* 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...
But I think the complex hacks are just the transformation into UTF 16
and calling of wcscoll(). If that's done from within pg_strcoll()
(after my patch), then I think it just works, right?
I can't easily test on windows, so perhaps I'm missing something. Does
the buildfarm have enough coverage here? Is it reasonable to try a
commit that removes the:
#ifdef WIN32
if (GetDatabaseEncoding() == PG_UTF8 &&
!(locale && locale->provider == COLLPROVIDER_ICU))
return;
#endif
along with my patch and see what I get out of the buildfarm?
Perhaps you have some follow-up work
planned, in which case it might be better to consider this in more
context.
I was also considering an optimization to use stack allocation for
short strings when doing the non-UTF8 icu comparison. I am seeing some
benefit there, but it seems to depend on the size of the stack buffer.
That suggests that maybe TEXTBUFSIZE is too large (1024) and perhaps we
should drop it down, but I need to investigate more.
In general, I'm trying to slowly get the locale stuff more isolated.
Regards,
Jeff Davis
Re: Refactor to introduce pg_strcoll().
Attached some new patches. I think you were right that the API of
pg_strcoll() was strange before, so I changed it to:
* pg_strcoll() takes nul-terminated arguments
* pg_strncoll() takes arguments and lengths
The new pg_strcoll()/pg_strncoll() api in 0001 seems much reasonable to
support in the long term, potentially with other callers.
Patch 0004 exports:
* pg_collate_icu() is for ICU and takes arguments and lengths
* pg_collate_libc() is for libc and takes nul-terminated arguments
for a tiny speedup because varstrfastcmp_locale() has both nul-
terminated arguments and their lengths.
On Fri, 2022-11-04 at 15:06 -0700, Jeff Davis wrote:
But I think the complex hacks are just the transformation into UTF 16
and calling of wcscoll(). If that's done from within pg_strcoll()
(after my patch), then I think it just works, right?
I included a patch (0005) to enable varstrfastcmp_locale on windows
with a server encoding of UTF-8. I don't have a great way of testing
this, but it seems like it should work.
I was also considering an optimization to use stack allocation for
short strings when doing the non-UTF8 icu comparison. I am seeing
some
benefit there
I also included this optimization in 0003: try to use the stack for
reasonable values; allocate on the heap for larger strings. I think
it's helping a bit.
Patch 0002 helps a lot more: for the case of ICU with a non-UTF8 server
encoding, the speedup is something like 30%. The reason is that
icu_to_uchar() currently calls ucnv_toUChars() twice: once to determine
the precise output buffer size required, and then again once it has the
buffer ready. But it's easy to just size the destination buffer
conservatively, because the maximum space required is enough to hold
twice the number of UChars as there are input characters[1]https://unicode-org.github.io/icu-docs/apidoc/dev/icu4c/ucnv_8h.html#ae1049fcb893783c860fe0f9d4da84939, plus the
terminating nul. That means we just call ucnv_toUChars() once, to do
the actual conversion.
My perf test was to use a quick hack to disable abbreviated keys (so
that it's doing more comparisons), and then just do a large ORDER BY
... COLLATE on a table with generated text. The text is random lorem
ipsum data, with some characters replaced by multibyte characters to
exercise some more interesting paths. If someone else has some more
sophisticated collation tests I'd be interested to try them.
Regards,
Jeff Davis
[1]: https://unicode-org.github.io/icu-docs/apidoc/dev/icu4c/ucnv_8h.html#ae1049fcb893783c860fe0f9d4da84939
https://unicode-org.github.io/icu-docs/apidoc/dev/icu4c/ucnv_8h.html#ae1049fcb893783c860fe0f9d4da84939
Attachments:
v3-0001-Introduce-pg_strcoll-and-pg_strncoll.patchtext/x-patch; charset=UTF-8; name=v3-0001-Introduce-pg_strcoll-and-pg_strncoll.patchDownload
From 29249d17b5580e87365c008b18c83db5528db37e Mon Sep 17 00:00:00 2001
From: Jeff Davis <jdavis@postgresql.org>
Date: Wed, 9 Nov 2022 08:58:08 -0800
Subject: [PATCH v3 1/5] Introduce pg_strcoll() and pg_strncoll().
Hide the special cases of the platform, collation provider, and
database encoding in pg_locale.c. Simplify varlena.c.
---
src/backend/utils/adt/pg_locale.c | 263 ++++++++++++++++++++++++++++++
src/backend/utils/adt/varlena.c | 230 +-------------------------
src/include/utils/pg_locale.h | 3 +
3 files changed, 268 insertions(+), 228 deletions(-)
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 2b42d9ccd8..94dc64c2d0 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -79,6 +79,12 @@
#include <shlwapi.h>
#endif
+/*
+ * This should be large enough that most strings will fit, but small enough
+ * that we feel comfortable putting it on the stack
+ */
+#define TEXTBUFLEN 1024
+
#define MAX_L10N_DATA 80
@@ -1731,6 +1737,263 @@ get_collation_actual_version(char collprovider, const char *collcollate)
return collversion;
}
+/*
+ * win32_utf8_wcscoll
+ *
+ * Convert UTF8 arguments to wide characters and invoke wcscoll() or
+ * wcscoll_l().
+ */
+#ifdef WIN32
+static int
+win32_utf8_wcscoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
+ pg_locale_t locale)
+{
+ char a1buf[TEXTBUFLEN];
+ char a2buf[TEXTBUFLEN];
+ char *a1p,
+ *a2p;
+ int a1len;
+ int a2len;
+ int r;
+ int result;
+
+ if (len1 >= TEXTBUFLEN / 2)
+ {
+ a1len = len1 * 2 + 2;
+ a1p = palloc(a1len);
+ }
+ else
+ {
+ a1len = TEXTBUFLEN;
+ a1p = a1buf;
+ }
+ if (len2 >= TEXTBUFLEN / 2)
+ {
+ a2len = len2 * 2 + 2;
+ a2p = palloc(a2len);
+ }
+ else
+ {
+ a2len = TEXTBUFLEN;
+ a2p = a2buf;
+ }
+
+ /* API does not work for zero-length input */
+ if (len1 == 0)
+ r = 0;
+ else
+ {
+ r = MultiByteToWideChar(CP_UTF8, 0, arg1, len1,
+ (LPWSTR) a1p, a1len / 2);
+ if (!r)
+ ereport(ERROR,
+ (errmsg("could not convert string to UTF-16: error code %lu",
+ GetLastError())));
+ }
+ ((LPWSTR) a1p)[r] = 0;
+
+ if (len2 == 0)
+ r = 0;
+ else
+ {
+ r = MultiByteToWideChar(CP_UTF8, 0, arg2, len2,
+ (LPWSTR) a2p, a2len / 2);
+ if (!r)
+ ereport(ERROR,
+ (errmsg("could not convert string to UTF-16: error code %lu",
+ GetLastError())));
+ }
+ ((LPWSTR) a2p)[r] = 0;
+
+ errno = 0;
+#ifdef HAVE_LOCALE_T
+ if (locale)
+ result = wcscoll_l((LPWSTR) a1p, (LPWSTR) a2p, locale->info.lt);
+ else
+#endif
+ result = wcscoll((LPWSTR) a1p, (LPWSTR) a2p);
+ if (result == 2147483647) /* _NLSCMPERROR; missing from mingw
+ * headers */
+ ereport(ERROR,
+ (errmsg("could not compare Unicode strings: %m")));
+
+ if (a1p != a1buf)
+ pfree(a1p);
+ if (a2p != a2buf)
+ pfree(a2p);
+
+ return result;
+}
+#endif /* WIN32 */
+
+/*
+ * Collate using the libc provider. Arguments must be nul-terminated.
+ */
+static int
+pg_collate_libc(const char *arg1, const char *arg2, pg_locale_t locale)
+{
+ int result;
+
+#ifdef WIN32
+ /* Win32 does not have UTF-8, so we need to map to UTF-16 */
+ if (GetDatabaseEncoding() == PG_UTF8)
+ {
+ size_t len1 = strlen(arg1);
+ size_t len2 = strlen(arg2);
+ result = win32_utf8_wcscoll(arg1, len1, arg2, len2, locale);
+ }
+ else
+#endif /* WIN32 */
+ if (locale)
+ {
+#ifdef HAVE_LOCALE_T
+ result = strcoll_l(arg1, arg2, locale->info.lt);
+#else
+ /* shouldn't happen */
+ elog(ERROR, "unsupported collprovider: %c", locale->provider);
+#endif
+ }
+ else
+ result = strcoll(arg1, arg2);
+
+ return result;
+}
+
+/*
+ * Collate using the icu provider.
+ */
+static int
+pg_collate_icu(const char *arg1, size_t len1, const char *arg2, size_t len2,
+ pg_locale_t locale)
+{
+#ifdef USE_ICU
+ int result;
+
+ Assert(locale->provider == COLLPROVIDER_ICU);
+
+#ifdef HAVE_UCOL_STRCOLLUTF8
+ if (GetDatabaseEncoding() == PG_UTF8)
+ {
+ UErrorCode status;
+
+ status = U_ZERO_ERROR;
+ result = ucol_strcollUTF8(locale->info.icu.ucol,
+ arg1, len1,
+ arg2, len2,
+ &status);
+ if (U_FAILURE(status))
+ ereport(ERROR,
+ (errmsg("collation failed: %s", u_errorName(status))));
+ }
+ else
+#endif
+ {
+ int32_t ulen1,
+ ulen2;
+ UChar *uchar1,
+ *uchar2;
+
+ ulen1 = icu_to_uchar(&uchar1, arg1, len1);
+ ulen2 = icu_to_uchar(&uchar2, arg2, len2);
+
+ result = ucol_strcoll(locale->info.icu.ucol,
+ uchar1, ulen1,
+ uchar2, ulen2);
+
+ pfree(uchar1);
+ pfree(uchar2);
+ }
+
+ return result;
+#else /* not USE_ICU */
+ /* shouldn't happen */
+ elog(ERROR, "unsupported collprovider: %c", locale->provider);
+#endif /* not USE_ICU */
+}
+
+/*
+ * pg_strcoll
+ *
+ * Call ucol_strcollUTF8(), ucol_strcoll(), strcoll(), strcoll_l(), wcscoll(),
+ * or wcscoll_l() as appropriate for the given locale, platform, and database
+ * encoding. If the locale is not specified, use the database collation.
+ *
+ * Arguments must be encoded in the database encoding and nul-terminated.
+ *
+ * If the collation is deterministic, break ties with strcmp().
+ */
+int
+pg_strcoll(const char *arg1, const char *arg2, pg_locale_t locale)
+{
+ int result;
+
+ if (locale && locale->provider == COLLPROVIDER_ICU)
+ {
+ size_t len1 = strlen(arg1);
+ size_t len2 = strlen(arg2);
+ result = pg_collate_icu(arg1, len1, arg2, len2, locale);
+ }
+ else
+ {
+ result = pg_collate_libc(arg1, arg2, locale);
+ }
+
+ /* Break tie if necessary. */
+ if (result == 0 && (!locale || locale->deterministic))
+ result = strcmp(arg1, arg2);
+
+ return result;
+}
+
+/*
+ * pg_strncoll
+ *
+ * Call ucol_strcollUTF8(), ucol_strcoll(), strcoll(), strcoll_l(), wcscoll(),
+ * or wcscoll_l() as appropriate for the given locale, platform, and database
+ * encoding. If the locale is not specified, use the database collation.
+ *
+ * Arguments must be encoded in the database encoding.
+ *
+ * If the collation is deterministic, break ties with memcmp(), and then with
+ * the string length.
+ */
+int
+pg_strncoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
+ pg_locale_t locale)
+{
+ int result;
+
+ if (locale && locale->provider == COLLPROVIDER_ICU)
+ {
+ result = pg_collate_icu(arg1, len1, arg2, len2, locale);
+ }
+ else
+ {
+ char *arg1n = palloc(len1 + 1);
+ char *arg2n = palloc(len2 + 1);
+
+ /* nul-terminate arguments */
+ memcpy(arg1n, arg1, len1);
+ arg1n[len1] = '\0';
+ memcpy(arg2n, arg2, len2);
+ arg2n[len2] = '\0';
+
+ result = pg_collate_libc(arg1n, arg2n, locale);
+
+ pfree(arg1n);
+ pfree(arg2n);
+ }
+
+ /* Break tie if necessary. */
+ if (result == 0 && (!locale || locale->deterministic))
+ {
+ result = memcmp(arg1, arg2, Min(len1, len2));
+ if ((result == 0) && (len1 != len2))
+ result = (len1 < len2) ? -1 : 1;
+ }
+
+ return result;
+}
#ifdef USE_ICU
/*
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index c5e7ee7ca2..c904bc0825 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -1535,10 +1535,6 @@ varstr_cmp(const char *arg1, int len1, const char *arg2, int len2, Oid collid)
}
else
{
- char a1buf[TEXTBUFLEN];
- char a2buf[TEXTBUFLEN];
- char *a1p,
- *a2p;
pg_locale_t mylocale;
mylocale = pg_newlocale_from_collation(collid);
@@ -1555,171 +1551,7 @@ varstr_cmp(const char *arg1, int len1, const char *arg2, int len2, Oid collid)
if (len1 == len2 && memcmp(arg1, arg2, len1) == 0)
return 0;
-#ifdef WIN32
- /* Win32 does not have UTF-8, so we need to map to UTF-16 */
- if (GetDatabaseEncoding() == PG_UTF8
- && (!mylocale || mylocale->provider == COLLPROVIDER_LIBC))
- {
- int a1len;
- int a2len;
- int r;
-
- if (len1 >= TEXTBUFLEN / 2)
- {
- a1len = len1 * 2 + 2;
- a1p = palloc(a1len);
- }
- else
- {
- a1len = TEXTBUFLEN;
- a1p = a1buf;
- }
- if (len2 >= TEXTBUFLEN / 2)
- {
- a2len = len2 * 2 + 2;
- a2p = palloc(a2len);
- }
- else
- {
- a2len = TEXTBUFLEN;
- a2p = a2buf;
- }
-
- /* stupid Microsloth API does not work for zero-length input */
- if (len1 == 0)
- r = 0;
- else
- {
- r = MultiByteToWideChar(CP_UTF8, 0, arg1, len1,
- (LPWSTR) a1p, a1len / 2);
- if (!r)
- ereport(ERROR,
- (errmsg("could not convert string to UTF-16: error code %lu",
- GetLastError())));
- }
- ((LPWSTR) a1p)[r] = 0;
-
- if (len2 == 0)
- r = 0;
- else
- {
- r = MultiByteToWideChar(CP_UTF8, 0, arg2, len2,
- (LPWSTR) a2p, a2len / 2);
- if (!r)
- ereport(ERROR,
- (errmsg("could not convert string to UTF-16: error code %lu",
- GetLastError())));
- }
- ((LPWSTR) a2p)[r] = 0;
-
- errno = 0;
-#ifdef HAVE_LOCALE_T
- if (mylocale)
- result = wcscoll_l((LPWSTR) a1p, (LPWSTR) a2p, mylocale->info.lt);
- else
-#endif
- result = wcscoll((LPWSTR) a1p, (LPWSTR) a2p);
- if (result == 2147483647) /* _NLSCMPERROR; missing from mingw
- * headers */
- ereport(ERROR,
- (errmsg("could not compare Unicode strings: %m")));
-
- /* Break tie if necessary. */
- if (result == 0 &&
- (!mylocale || mylocale->deterministic))
- {
- result = memcmp(arg1, arg2, Min(len1, len2));
- if ((result == 0) && (len1 != len2))
- result = (len1 < len2) ? -1 : 1;
- }
-
- if (a1p != a1buf)
- pfree(a1p);
- if (a2p != a2buf)
- pfree(a2p);
-
- return result;
- }
-#endif /* WIN32 */
-
- if (len1 >= TEXTBUFLEN)
- a1p = (char *) palloc(len1 + 1);
- else
- a1p = a1buf;
- if (len2 >= TEXTBUFLEN)
- a2p = (char *) palloc(len2 + 1);
- else
- a2p = a2buf;
-
- memcpy(a1p, arg1, len1);
- a1p[len1] = '\0';
- memcpy(a2p, arg2, len2);
- a2p[len2] = '\0';
-
- if (mylocale)
- {
- if (mylocale->provider == COLLPROVIDER_ICU)
- {
-#ifdef USE_ICU
-#ifdef HAVE_UCOL_STRCOLLUTF8
- if (GetDatabaseEncoding() == PG_UTF8)
- {
- UErrorCode status;
-
- status = U_ZERO_ERROR;
- result = ucol_strcollUTF8(mylocale->info.icu.ucol,
- arg1, len1,
- arg2, len2,
- &status);
- if (U_FAILURE(status))
- ereport(ERROR,
- (errmsg("collation failed: %s", u_errorName(status))));
- }
- else
-#endif
- {
- int32_t ulen1,
- ulen2;
- UChar *uchar1,
- *uchar2;
-
- ulen1 = icu_to_uchar(&uchar1, arg1, len1);
- ulen2 = icu_to_uchar(&uchar2, arg2, len2);
-
- result = ucol_strcoll(mylocale->info.icu.ucol,
- uchar1, ulen1,
- uchar2, ulen2);
-
- pfree(uchar1);
- pfree(uchar2);
- }
-#else /* not USE_ICU */
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", mylocale->provider);
-#endif /* not USE_ICU */
- }
- else
- {
-#ifdef HAVE_LOCALE_T
- result = strcoll_l(a1p, a2p, mylocale->info.lt);
-#else
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", mylocale->provider);
-#endif
- }
- }
- else
- result = strcoll(a1p, a2p);
-
- /* Break tie if necessary. */
- if (result == 0 &&
- (!mylocale || mylocale->deterministic))
- result = strcmp(a1p, a2p);
-
- if (a1p != a1buf)
- pfree(a1p);
- if (a2p != a2buf)
- pfree(a2p);
+ result = pg_strncoll(arg1, len1, arg2, len2, mylocale);
}
return result;
@@ -2377,65 +2209,7 @@ varstrfastcmp_locale(char *a1p, int len1, char *a2p, int len2, SortSupport ssup)
return sss->last_returned;
}
- if (sss->locale)
- {
- if (sss->locale->provider == COLLPROVIDER_ICU)
- {
-#ifdef USE_ICU
-#ifdef HAVE_UCOL_STRCOLLUTF8
- if (GetDatabaseEncoding() == PG_UTF8)
- {
- UErrorCode status;
-
- status = U_ZERO_ERROR;
- result = ucol_strcollUTF8(sss->locale->info.icu.ucol,
- a1p, len1,
- a2p, len2,
- &status);
- if (U_FAILURE(status))
- ereport(ERROR,
- (errmsg("collation failed: %s", u_errorName(status))));
- }
- else
-#endif
- {
- int32_t ulen1,
- ulen2;
- UChar *uchar1,
- *uchar2;
-
- ulen1 = icu_to_uchar(&uchar1, a1p, len1);
- ulen2 = icu_to_uchar(&uchar2, a2p, len2);
-
- result = ucol_strcoll(sss->locale->info.icu.ucol,
- uchar1, ulen1,
- uchar2, ulen2);
-
- pfree(uchar1);
- pfree(uchar2);
- }
-#else /* not USE_ICU */
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", sss->locale->provider);
-#endif /* not USE_ICU */
- }
- else
- {
-#ifdef HAVE_LOCALE_T
- result = strcoll_l(sss->buf1, sss->buf2, sss->locale->info.lt);
-#else
- /* shouldn't happen */
- elog(ERROR, "unsupported collprovider: %c", sss->locale->provider);
-#endif
- }
- }
- else
- result = strcoll(sss->buf1, sss->buf2);
-
- /* Break tie if necessary. */
- if (result == 0 &&
- (!sss->locale || sss->locale->deterministic))
- result = strcmp(sss->buf1, sss->buf2);
+ result = pg_strcoll(sss->buf1, sss->buf2, sss->locale);
/* Cache result, perhaps saving an expensive strcoll() call next time */
sss->cache_blob = false;
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index a875942123..bf70ae08ca 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -100,6 +100,9 @@ extern void make_icu_collator(const char *iculocstr,
extern pg_locale_t pg_newlocale_from_collation(Oid collid);
extern char *get_collation_actual_version(char collprovider, const char *collcollate);
+extern int pg_strcoll(const char *arg1, const char *arg2, pg_locale_t locale);
+extern int pg_strncoll(const char *arg1, size_t len1,
+ const char *arg2, size_t len2, pg_locale_t locale);
#ifdef USE_ICU
extern int32_t icu_to_uchar(UChar **buff_uchar, const char *buff, size_t nbytes);
--
2.34.1
v3-0002-Refactor-icu_to_uchar.patchtext/x-patch; charset=UTF-8; name=v3-0002-Refactor-icu_to_uchar.patchDownload
From dd14c838acc65aa90a6456222d829ae1986f1c41 Mon Sep 17 00:00:00 2001
From: Jeff Davis <jdavis@postgresql.org>
Date: Tue, 8 Nov 2022 16:46:27 -0800
Subject: [PATCH v3 2/5] Refactor icu_to_uchar().
Separate buffer allocation and conversion so that the caller can
supply its own buffer. This also enables the caller to size the
destination to the maximum requirement of twice the number of input
characters, rather than go through ucnv_toUChars() to compute the
precise destination buffer size requirement (which is more expensive).
---
src/backend/utils/adt/pg_locale.c | 128 +++++++++++++++++++++---------
1 file changed, 92 insertions(+), 36 deletions(-)
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 94dc64c2d0..17857067a3 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -129,6 +129,19 @@ static char *IsoLocaleName(const char *);
#endif
#ifdef USE_ICU
+/*
+ * Converter object for converting between ICU's UChar strings and C strings
+ * in database encoding. Since the database encoding doesn't change, we only
+ * need one of these per session.
+ */
+static UConverter *icu_converter = NULL;
+
+static void init_icu_converter(void);
+static size_t uchar_length(UConverter *converter,
+ const char *str, size_t len);
+static int32_t uchar_convert(UConverter *converter,
+ UChar *dest, int32_t destlen,
+ const char *str, size_t srclen);
static void icu_set_collation_attributes(UCollator *collator, const char *loc);
#endif
@@ -1859,6 +1872,47 @@ pg_collate_libc(const char *arg1, const char *arg2, pg_locale_t locale)
return result;
}
+/*
+ * Collate using the icu provider when the database encoding is not UTF-8.
+ */
+#ifdef USE_ICU
+static int
+pg_collate_icu_no_utf8(const char *arg1, size_t len1,
+ const char *arg2, size_t len2, pg_locale_t locale)
+{
+ int32_t ulen1;
+ int32_t ulen2;
+ size_t bufsize1;
+ size_t bufsize2;
+ UChar *uchar1,
+ *uchar2;
+ int result;
+
+ init_icu_converter();
+
+ ulen1 = uchar_length(icu_converter, arg1, len1);
+ ulen2 = uchar_length(icu_converter, arg2, len2);
+
+ bufsize1 = (ulen1 + 1) * sizeof(UChar);
+ bufsize2 = (ulen2 + 1) * sizeof(UChar);
+
+ uchar1 = palloc(bufsize1);
+ uchar2 = palloc(bufsize2);
+
+ ulen1 = uchar_convert(icu_converter, uchar1, ulen1 + 1, arg1, len1);
+ ulen2 = uchar_convert(icu_converter, uchar2, ulen2 + 1, arg2, len2);
+
+ result = ucol_strcoll(locale->info.icu.ucol,
+ uchar1, ulen1,
+ uchar2, ulen2);
+
+ pfree(uchar1);
+ pfree(uchar2);
+
+ return result;
+}
+#endif
+
/*
* Collate using the icu provider.
*/
@@ -1888,20 +1942,7 @@ pg_collate_icu(const char *arg1, size_t len1, const char *arg2, size_t len2,
else
#endif
{
- int32_t ulen1,
- ulen2;
- UChar *uchar1,
- *uchar2;
-
- ulen1 = icu_to_uchar(&uchar1, arg1, len1);
- ulen2 = icu_to_uchar(&uchar2, arg2, len2);
-
- result = ucol_strcoll(locale->info.icu.ucol,
- uchar1, ulen1,
- uchar2, ulen2);
-
- pfree(uchar1);
- pfree(uchar2);
+ result = pg_collate_icu_no_utf8(arg1, len1, arg2, len2, locale);
}
return result;
@@ -1996,13 +2037,6 @@ pg_strncoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
}
#ifdef USE_ICU
-/*
- * Converter object for converting between ICU's UChar strings and C strings
- * in database encoding. Since the database encoding doesn't change, we only
- * need one of these per session.
- */
-static UConverter *icu_converter = NULL;
-
static void
init_icu_converter(void)
{
@@ -2030,6 +2064,39 @@ init_icu_converter(void)
icu_converter = conv;
}
+/*
+ * Find length, in UChars, of given string if converted to UChar string.
+ */
+static size_t
+uchar_length(UConverter *converter, const char *str, size_t len)
+{
+ UErrorCode status = U_ZERO_ERROR;
+ int32_t ulen;
+ ulen = ucnv_toUChars(converter, NULL, 0, str, len, &status);
+ if (U_FAILURE(status) && status != U_BUFFER_OVERFLOW_ERROR)
+ ereport(ERROR,
+ (errmsg("%s failed: %s", "ucnv_toUChars", u_errorName(status))));
+ return ulen;
+}
+
+/*
+ * Convert the given source string into a UChar string, stored in dest, and
+ * return the length (in UChars).
+ */
+static int32_t
+uchar_convert(UConverter *converter, UChar *dest, int32_t destlen,
+ const char *src, size_t srclen)
+{
+ UErrorCode status = U_ZERO_ERROR;
+ int32_t ulen;
+ status = U_ZERO_ERROR;
+ ulen = ucnv_toUChars(converter, dest, destlen, src, srclen, &status);
+ if (U_FAILURE(status))
+ ereport(ERROR,
+ (errmsg("%s failed: %s", "ucnv_toUChars", u_errorName(status))));
+ return ulen;
+}
+
/*
* Convert a string in the database encoding into a string of UChars.
*
@@ -2045,26 +2112,15 @@ init_icu_converter(void)
int32_t
icu_to_uchar(UChar **buff_uchar, const char *buff, size_t nbytes)
{
- UErrorCode status;
- int32_t len_uchar;
+ int32_t len_uchar;
init_icu_converter();
- status = U_ZERO_ERROR;
- len_uchar = ucnv_toUChars(icu_converter, NULL, 0,
- buff, nbytes, &status);
- if (U_FAILURE(status) && status != U_BUFFER_OVERFLOW_ERROR)
- ereport(ERROR,
- (errmsg("%s failed: %s", "ucnv_toUChars", u_errorName(status))));
+ len_uchar = uchar_length(icu_converter, buff, nbytes);
*buff_uchar = palloc((len_uchar + 1) * sizeof(**buff_uchar));
-
- status = U_ZERO_ERROR;
- len_uchar = ucnv_toUChars(icu_converter, *buff_uchar, len_uchar + 1,
- buff, nbytes, &status);
- if (U_FAILURE(status))
- ereport(ERROR,
- (errmsg("%s failed: %s", "ucnv_toUChars", u_errorName(status))));
+ len_uchar = uchar_convert(icu_converter,
+ *buff_uchar, len_uchar + 1, buff, nbytes);
return len_uchar;
}
--
2.34.1
v3-0003-Optimize-buffer-allocation-for-pg_strcoll-pg_strn.patchtext/x-patch; charset=UTF-8; name=v3-0003-Optimize-buffer-allocation-for-pg_strcoll-pg_strn.patchDownload
From 3f6cde0dea813ad45d05bd7655a66bf17a88d58b Mon Sep 17 00:00:00 2001
From: Jeff Davis <jdavis@postgresql.org>
Date: Wed, 9 Nov 2022 12:26:38 -0800
Subject: [PATCH v3 3/5] Optimize buffer allocation for
pg_strcoll()/pg_strncoll().
When it's necessary to convert the arguments before comparison
(e.g. to a UChar string), use stack space if the arguments are small
enough to fit; otherwise fall back to a heap allocation.
---
src/backend/utils/adt/pg_locale.c | 70 +++++++++++++++----------------
1 file changed, 34 insertions(+), 36 deletions(-)
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 17857067a3..7c29519214 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -1761,35 +1761,20 @@ static int
win32_utf8_wcscoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
pg_locale_t locale)
{
- char a1buf[TEXTBUFLEN];
- char a2buf[TEXTBUFLEN];
+ char sbuf[TEXTBUFLEN];
+ char *buf = sbuf;
char *a1p,
*a2p;
- int a1len;
- int a2len;
+ int a1len = len1 * 2 + 2;
+ int a2len = len2 * 2 + 2;
int r;
int result;
- if (len1 >= TEXTBUFLEN / 2)
- {
- a1len = len1 * 2 + 2;
- a1p = palloc(a1len);
- }
- else
- {
- a1len = TEXTBUFLEN;
- a1p = a1buf;
- }
- if (len2 >= TEXTBUFLEN / 2)
- {
- a2len = len2 * 2 + 2;
- a2p = palloc(a2len);
- }
- else
- {
- a2len = TEXTBUFLEN;
- a2p = a2buf;
- }
+ if (a1len + a2len > TEXTBUFLEN)
+ buf = palloc(a1len + a2len);
+
+ a1p = buf;
+ a2p = buf + a1len;
/* API does not work for zero-length input */
if (len1 == 0)
@@ -1830,10 +1815,8 @@ win32_utf8_wcscoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
ereport(ERROR,
(errmsg("could not compare Unicode strings: %m")));
- if (a1p != a1buf)
- pfree(a1p);
- if (a2p != a2buf)
- pfree(a2p);
+ if (buf != sbuf)
+ pfree(buf);
return result;
}
@@ -1880,6 +1863,8 @@ static int
pg_collate_icu_no_utf8(const char *arg1, size_t len1,
const char *arg2, size_t len2, pg_locale_t locale)
{
+ char sbuf[TEXTBUFLEN];
+ char *buf = sbuf;
int32_t ulen1;
int32_t ulen2;
size_t bufsize1;
@@ -1896,8 +1881,11 @@ pg_collate_icu_no_utf8(const char *arg1, size_t len1,
bufsize1 = (ulen1 + 1) * sizeof(UChar);
bufsize2 = (ulen2 + 1) * sizeof(UChar);
- uchar1 = palloc(bufsize1);
- uchar2 = palloc(bufsize2);
+ if (bufsize1 + bufsize2 > TEXTBUFLEN)
+ buf = palloc(bufsize1 + bufsize2);
+
+ uchar1 = (UChar *) buf;
+ uchar2 = (UChar *) (buf + bufsize1);
ulen1 = uchar_convert(icu_converter, uchar1, ulen1 + 1, arg1, len1);
ulen2 = uchar_convert(icu_converter, uchar2, ulen2 + 1, arg2, len2);
@@ -1906,8 +1894,8 @@ pg_collate_icu_no_utf8(const char *arg1, size_t len1,
uchar1, ulen1,
uchar2, ulen2);
- pfree(uchar1);
- pfree(uchar2);
+ if (buf != sbuf)
+ pfree(buf);
return result;
}
@@ -2010,8 +1998,18 @@ pg_strncoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
}
else
{
- char *arg1n = palloc(len1 + 1);
- char *arg2n = palloc(len2 + 1);
+ char sbuf[TEXTBUFLEN];
+ char *buf = sbuf;
+ size_t bufsize1 = len1 + 1;
+ size_t bufsize2 = len2 + 1;
+ char *arg1n;
+ char *arg2n;
+
+ if (bufsize1 + bufsize2 > TEXTBUFLEN)
+ buf = palloc(bufsize1 + bufsize2);
+
+ arg1n = buf;
+ arg2n = buf + bufsize1;
/* nul-terminate arguments */
memcpy(arg1n, arg1, len1);
@@ -2021,8 +2019,8 @@ pg_strncoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
result = pg_collate_libc(arg1n, arg2n, locale);
- pfree(arg1n);
- pfree(arg2n);
+ if (buf != sbuf)
+ pfree(buf);
}
/* Break tie if necessary. */
--
2.34.1
v3-0004-Export-pg_collate_libc-and-pg_collate_icu.patchtext/x-patch; charset=UTF-8; name=v3-0004-Export-pg_collate_libc-and-pg_collate_icu.patchDownload
From 8aea65b0a32a0bee9432ccd537d2852e4cc74087 Mon Sep 17 00:00:00 2001
From: Jeff Davis <jdavis@postgresql.org>
Date: Wed, 9 Nov 2022 17:00:01 -0800
Subject: [PATCH v3 4/5] Export pg_collate_libc() and pg_collate_icu().
Minor optimization for callers such as varstrfastcmp_locale(), which
has both nul-terminated arguments, and also the string length.
---
src/backend/utils/adt/pg_locale.c | 40 ++++++++++++++++---------------
src/backend/utils/adt/varlena.c | 6 ++++-
src/include/utils/pg_locale.h | 4 ++++
3 files changed, 30 insertions(+), 20 deletions(-)
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 7c29519214..df809891ac 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -1824,8 +1824,10 @@ win32_utf8_wcscoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
/*
* Collate using the libc provider. Arguments must be nul-terminated.
+ *
+ * If the collation is deterministic, break ties with strcmp().
*/
-static int
+int
pg_collate_libc(const char *arg1, const char *arg2, pg_locale_t locale)
{
int result;
@@ -1852,6 +1854,10 @@ pg_collate_libc(const char *arg1, const char *arg2, pg_locale_t locale)
else
result = strcoll(arg1, arg2);
+ /* Break tie if necessary. */
+ if (result == 0 && (!locale || locale->deterministic))
+ result = strcmp(arg1, arg2);
+
return result;
}
@@ -1865,8 +1871,8 @@ pg_collate_icu_no_utf8(const char *arg1, size_t len1,
{
char sbuf[TEXTBUFLEN];
char *buf = sbuf;
- int32_t ulen1;
- int32_t ulen2;
+ int32_t ulen1 = len1 * 2;
+ int32_t ulen2 = len2 * 2;
size_t bufsize1;
size_t bufsize2;
UChar *uchar1,
@@ -1875,9 +1881,6 @@ pg_collate_icu_no_utf8(const char *arg1, size_t len1,
init_icu_converter();
- ulen1 = uchar_length(icu_converter, arg1, len1);
- ulen2 = uchar_length(icu_converter, arg2, len2);
-
bufsize1 = (ulen1 + 1) * sizeof(UChar);
bufsize2 = (ulen2 + 1) * sizeof(UChar);
@@ -1903,8 +1906,11 @@ pg_collate_icu_no_utf8(const char *arg1, size_t len1,
/*
* Collate using the icu provider.
+ *
+ * If the collation is deterministic, break ties with memcmp(), and then with
+ * the string length.
*/
-static int
+int
pg_collate_icu(const char *arg1, size_t len1, const char *arg2, size_t len2,
pg_locale_t locale)
{
@@ -1933,6 +1939,14 @@ pg_collate_icu(const char *arg1, size_t len1, const char *arg2, size_t len2,
result = pg_collate_icu_no_utf8(arg1, len1, arg2, len2, locale);
}
+ /* Break tie if necessary. */
+ if (result == 0 && (!locale || locale->deterministic))
+ {
+ result = memcmp(arg1, arg2, Min(len1, len2));
+ if ((result == 0) && (len1 != len2))
+ result = (len1 < len2) ? -1 : 1;
+ }
+
return result;
#else /* not USE_ICU */
/* shouldn't happen */
@@ -1967,10 +1981,6 @@ pg_strcoll(const char *arg1, const char *arg2, pg_locale_t locale)
result = pg_collate_libc(arg1, arg2, locale);
}
- /* Break tie if necessary. */
- if (result == 0 && (!locale || locale->deterministic))
- result = strcmp(arg1, arg2);
-
return result;
}
@@ -2023,14 +2033,6 @@ pg_strncoll(const char *arg1, size_t len1, const char *arg2, size_t len2,
pfree(buf);
}
- /* Break tie if necessary. */
- if (result == 0 && (!locale || locale->deterministic))
- {
- result = memcmp(arg1, arg2, Min(len1, len2));
- if ((result == 0) && (len1 != len2))
- result = (len1 < len2) ? -1 : 1;
- }
-
return result;
}
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index c904bc0825..5ebfe3acb7 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -2209,7 +2209,11 @@ varstrfastcmp_locale(char *a1p, int len1, char *a2p, int len2, SortSupport ssup)
return sss->last_returned;
}
- result = pg_strcoll(sss->buf1, sss->buf2, sss->locale);
+ if (sss->locale && sss->locale->provider == COLLPROVIDER_ICU)
+ result = pg_collate_icu(sss->buf1, len1, sss->buf2, len2,
+ sss->locale);
+ else
+ result = pg_collate_libc(sss->buf1, sss->buf2, sss->locale);
/* Cache result, perhaps saving an expensive strcoll() call next time */
sss->cache_blob = false;
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index bf70ae08ca..5f7a8ea435 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -103,6 +103,10 @@ extern char *get_collation_actual_version(char collprovider, const char *collcol
extern int pg_strcoll(const char *arg1, const char *arg2, pg_locale_t locale);
extern int pg_strncoll(const char *arg1, size_t len1,
const char *arg2, size_t len2, pg_locale_t locale);
+extern int pg_collate_libc(const char *arg1, const char *arg2,
+ pg_locale_t locale);
+extern int pg_collate_icu(const char *arg1, size_t len1,
+ const char *arg2, size_t len2, pg_locale_t locale);
#ifdef USE_ICU
extern int32_t icu_to_uchar(UChar **buff_uchar, const char *buff, size_t nbytes);
--
2.34.1
v3-0005-Allow-windows-to-use-varlenafastcmp_locale.patchtext/x-patch; charset=UTF-8; name=v3-0005-Allow-windows-to-use-varlenafastcmp_locale.patchDownload
From 211dfc48f879b70fe18326f42bcd29ccefdf2c03 Mon Sep 17 00:00:00 2001
From: Jeff Davis <jdavis@postgresql.org>
Date: Wed, 9 Nov 2022 13:56:19 -0800
Subject: [PATCH v3 5/5] Allow windows to use varlenafastcmp_locale.
Now that the combination of windows with the libc provider and UTF-8
for the database encoding is handled by pg_collate_libc(), we can
support varlenafastcmp_locale for windows as well.
---
src/backend/utils/adt/varlena.c | 14 --------------
1 file changed, 14 deletions(-)
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 5ebfe3acb7..e23c2ca31e 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -1887,20 +1887,6 @@ varstr_sortsupport(SortSupport ssup, Oid typid, Oid collid)
*/
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
-
/*
* We use varlenafastcmp_locale except for type NAME.
*/
--
2.34.1
Re: Refactor to introduce pg_strcoll().
+ /* Win32 does not have UTF-8, so we need to map to UTF-16 */
I wonder if this is still true. I think in Windows 10+ you can enable
UTF-8 support. Then could you use strcoll_l() directly? I struggled
to understand that, but I am a simple Unix hobbit from the shire so I
dunno. (Perhaps the *whole OS* has to be in that mode, so you might
have to do a runtime test? This was discussed in another thread that
mostly left me confused[1]/messages/by-id/CA+hUKGJ=XThErgAQRoqfCy1bKPxXVuF0=2zDbB+SxDs59pv7Fw@mail.gmail.com.).
And that leads to another thought. We have an old comment
"Unfortunately, there is no strncoll(), so ...". Curiously, Windows
does actually have strncoll_l() (as do some other libcs out there).
So after skipping the expansion to wchar_t, one might think you could
avoid the extra copy required to nul-terminate the string (and hope
that it doesn't make an extra copy internally, far from given).
Unfortunately it seems to be defined in a strange way that doesn't
look like your pg_strncoll_XXX() convention: it has just one length
parameter, not one for each string. That is, it's designed for
comparing prefixes of strings, not for working with
non-null-terminated strings. I'm not entirely sure if the interface
makes sense at all! Is it measuring in 'chars' or 'encoded
characters'? I would guess the former, like strncpy() et al, but then
what does it mean if it chops a UTF-8 sequence in half? And at a
higher level, if you wanted to use it for our purpose, you'd
presumably need Min(s1_len, s2_len), but I wonder if there are string
pairs that would sort in a different order if the collation algorithm
could see more characters after that? For example, in Dutch "ij" is
sometimes treated like a letter that sorts differently than "i" + "j"
normally would, so if you arbitrarily chop that "j" off while
comparing common-length prefix you might get into trouble; likewise
for "aa" in Danish. Perhaps these sorts of problems explain why it's
not in the standard (though I see it was at some point in some kind of
draft; I don't grok the C standards process enough to track down what
happened but WG20/WG14 draft N1027[2]https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1027.pdf clearly contains strncoll_l()
alongside the stuff that we know and use today). Or maybe I'm
underthinking it.
[1]: /messages/by-id/CA+hUKGJ=XThErgAQRoqfCy1bKPxXVuF0=2zDbB+SxDs59pv7Fw@mail.gmail.com
[2]: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1027.pdf