Remove lc_collate_is_c().

Instead just look up the collation and check collate_is_c field.

Author: Andreas Karlsson
Discussion: https://postgr.es/m/60929555-4709-40a7-b136-bcb44cff5a3c@proxel.se

src/backend/access/spgist/spgtextproc.c

@@ -427,7 +427,7 @@ spg_text_inner_consistent(PG_FUNCTION_ARGS)
 {
 	spgInnerConsistentIn *in = (spgInnerConsistentIn *) PG_GETARG_POINTER(0);
 	spgInnerConsistentOut *out = (spgInnerConsistentOut *) PG_GETARG_POINTER(1);
-	bool		collate_is_c = lc_collate_is_c(PG_GET_COLLATION());
+	bool		collate_is_c = pg_newlocale_from_collation(PG_GET_COLLATION())->collate_is_c;
 	text	   *reconstructedValue;
 	text	   *reconstrText;
 	int			maxReconstrLen;

src/backend/commands/collationcmds.c

@@ -377,13 +377,9 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e
 	if (!OidIsValid(newoid))
 		return InvalidObjectAddress;
 
-	/*
-	 * Check that the locales can be loaded.  NB: pg_newlocale_from_collation
-	 * is only supposed to be called on non-C-equivalent locales.
-	 */
+	/* Check that the locales can be loaded. */
 	CommandCounterIncrement();
-	if (!lc_collate_is_c(newoid) || !lc_ctype_is_c(newoid))
-		(void) pg_newlocale_from_collation(newoid);
+	(void) pg_newlocale_from_collation(newoid);
 
 	ObjectAddressSet(address, CollationRelationId, newoid);
 

src/backend/utils/adt/like_support.c

@@ -433,7 +433,7 @@ match_pattern_prefix(Node *leftop,
 	 * collation.
 	 */
 	if (collation_aware &&
-		!lc_collate_is_c(indexcollation))
+		!pg_newlocale_from_collation(indexcollation)->collate_is_c)
 		return NIL;
 
 	/*
@@ -1603,7 +1603,7 @@ make_greater_string(const Const *str_const, FmgrInfo *ltproc, Oid collation)
 		else
 			workstr = TextDatumGetCString(str_const->constvalue);
 		len = strlen(workstr);
-		if (lc_collate_is_c(collation) || len == 0)
+		if (len == 0 || pg_newlocale_from_collation(collation)->collate_is_c)
 			cmpstr = str_const->constvalue;
 		else
 		{

src/backend/utils/adt/pg_locale.c

@@ -1266,33 +1266,6 @@ lookup_collation_cache(Oid collation)
 	return cache_entry;
 }
 
-
-/*
- * Detect whether collation's LC_COLLATE property is C
- */
-bool
-lc_collate_is_c(Oid collation)
-{
-	/*
-	 * If we're asked about "collation 0", return false, so that the code will
-	 * go into the non-C path and report that the collation is bogus.
-	 */
-	if (!OidIsValid(collation))
-		return false;
-
-	/*
-	 * If we're asked about the built-in C/POSIX collations, we know that.
-	 */
-	if (collation == C_COLLATION_OID ||
-		collation == POSIX_COLLATION_OID)
-		return true;
-
-	/*
-	 * Otherwise, we have to consult pg_collation, but we cache that.
-	 */
-	return pg_newlocale_from_collation(collation)->collate_is_c;
-}
-
 /*
  * Detect whether collation's LC_CTYPE property is C
  */
@@ -1571,12 +1544,12 @@ pg_newlocale_from_collation(Oid collid)
 {
 	collation_cache_entry *cache_entry;
 
-	/* Callers must pass a valid OID */
-	Assert(OidIsValid(collid));
-
 	if (collid == DEFAULT_COLLATION_OID)
 		return &default_locale;
 
+	if (!OidIsValid(collid))
+		elog(ERROR, "cache lookup failed for collation %u", collid);
+
 	if (last_collation_cache_oid == collid)
 		return last_collation_cache_locale;
 

src/backend/utils/adt/selfuncs.c

@@ -4646,6 +4646,7 @@ static char *
 convert_string_datum(Datum value, Oid typid, Oid collid, bool *failure)
 {
 	char	   *val;
+	pg_locale_t mylocale;
 
 	switch (typid)
 	{
@@ -4671,9 +4672,10 @@ convert_string_datum(Datum value, Oid typid, Oid collid, bool *failure)
 			return NULL;
 	}
 
-	if (!lc_collate_is_c(collid))
+	mylocale = pg_newlocale_from_collation(collid);
+
+	if (!mylocale->collate_is_c)
 	{
-		pg_locale_t mylocale = pg_newlocale_from_collation(collid);
 		char	   *xfrmstr;
 		size_t		xfrmlen;
 		size_t		xfrmlen2 PG_USED_FOR_ASSERTS_ONLY;

src/backend/utils/adt/varchar.c

@@ -748,20 +748,16 @@ bpchareq(PG_FUNCTION_ARGS)
 				len2;
 	bool		result;
 	Oid			collid = PG_GET_COLLATION();
-	bool		locale_is_c = false;
-	pg_locale_t mylocale = 0;
+	pg_locale_t mylocale;
 
 	check_collation_set(collid);
 
 	len1 = bcTruelen(arg1);
 	len2 = bcTruelen(arg2);
 
-	if (lc_collate_is_c(collid))
-		locale_is_c = true;
-	else
-		mylocale = pg_newlocale_from_collation(collid);
+	mylocale = pg_newlocale_from_collation(collid);
 
-	if (locale_is_c || pg_locale_deterministic(mylocale))
+	if (mylocale->collate_is_c || pg_locale_deterministic(mylocale))
 	{
 		/*
 		 * Since we only care about equality or not-equality, we can avoid all
@@ -793,20 +789,16 @@ bpcharne(PG_FUNCTION_ARGS)
 				len2;
 	bool		result;
 	Oid			collid = PG_GET_COLLATION();
-	bool		locale_is_c = false;
-	pg_locale_t mylocale = 0;
+	pg_locale_t mylocale;
 
 	check_collation_set(collid);
 
 	len1 = bcTruelen(arg1);
 	len2 = bcTruelen(arg2);
 
-	if (lc_collate_is_c(collid))
-		locale_is_c = true;
-	else
-		mylocale = pg_newlocale_from_collation(collid);
+	mylocale = pg_newlocale_from_collation(collid);
 
-	if (locale_is_c || pg_locale_deterministic(mylocale))
+	if (mylocale->collate_is_c || pg_locale_deterministic(mylocale))
 	{
 		/*
 		 * Since we only care about equality or not-equality, we can avoid all

src/backend/utils/adt/varlena.c

@@ -1538,10 +1538,13 @@ int
 varstr_cmp(const char *arg1, int len1, const char *arg2, int len2, Oid collid)
 {
 	int			result;
+	pg_locale_t mylocale;
 
 	check_collation_set(collid);
 
-	if (lc_collate_is_c(collid))
+	mylocale = pg_newlocale_from_collation(collid);
+
+	if (mylocale->collate_is_c)
 	{
 		result = memcmp(arg1, arg2, Min(len1, len2));
 		if ((result == 0) && (len1 != len2))
@@ -1549,10 +1552,6 @@ varstr_cmp(const char *arg1, int len1, const char *arg2, int len2, Oid collid)
 	}
 	else
 	{
-		pg_locale_t mylocale;
-
-		mylocale = pg_newlocale_from_collation(collid);
-
 		/*
 		 * memcmp() can't tell us which of two unequal strings sorts first,
 		 * but it's a cheap way to tell if they're equal.  Testing shows that
@@ -1859,10 +1858,12 @@ varstr_sortsupport(SortSupport ssup, Oid typid, Oid collid)
 	bool		abbreviate = ssup->abbreviate;
 	bool		collate_c = false;
 	VarStringSortSupport *sss;
-	pg_locale_t locale = 0;
+	pg_locale_t locale;
 
 	check_collation_set(collid);
 
+	locale = pg_newlocale_from_collation(collid);
+
 	/*
 	 * If possible, set ssup->comparator to a function which can be used to
 	 * directly compare two datums.  If we can do this, we'll avoid the
@@ -1876,7 +1877,7 @@ varstr_sortsupport(SortSupport ssup, Oid typid, Oid collid)
 	 * varstrfastcmp_c, bpcharfastcmp_c, or namefastcmp_c, all of which use
 	 * memcmp() rather than strcoll().
 	 */
-	if (lc_collate_is_c(collid))
+	if (locale->collate_is_c)
 	{
 		if (typid == BPCHAROID)
 			ssup->comparator = bpcharfastcmp_c;
@@ -1893,13 +1894,6 @@ varstr_sortsupport(SortSupport ssup, Oid typid, Oid collid)
 	}
 	else
 	{
-		/*
-		 * We need a collation-sensitive comparison.  To make things faster,
-		 * we'll figure out the collation based on the locale id and cache the
-		 * result.
-		 */
-		locale = pg_newlocale_from_collation(collid);
-
 		/*
 		 * We use varlenafastcmp_locale except for type NAME.
 		 */
@@ -1950,7 +1944,10 @@ varstr_sortsupport(SortSupport ssup, Oid typid, Oid collid)
 		sss->last_len2 = -1;
 		/* Initialize */
 		sss->last_returned = 0;
-		sss->locale = locale;
+		if (collate_c)
+			sss->locale = NULL;
+		else
+			sss->locale = locale;
 
 		/*
 		 * To avoid somehow confusing a strxfrm() blob and an original string,
@@ -2536,12 +2533,15 @@ btvarstrequalimage(PG_FUNCTION_ARGS)
 {
 	/* Oid		opcintype = PG_GETARG_OID(0); */
 	Oid			collid = PG_GET_COLLATION();
+	pg_locale_t locale;
 
 	check_collation_set(collid);
 
-	if (lc_collate_is_c(collid) ||
+	locale = pg_newlocale_from_collation(collid);
+
+	if (locale->collate_is_c ||
 		collid == DEFAULT_COLLATION_OID ||
-		get_collation_isdeterministic(collid))
+		pg_locale_deterministic(locale))
 		PG_RETURN_BOOL(true);
 	else
 		PG_RETURN_BOOL(false);

src/include/utils/pg_locale.h

@@ -54,7 +54,6 @@ extern PGDLLIMPORT bool database_ctype_is_c;
 extern bool check_locale(int category, const char *locale, char **canonname);
 extern char *pg_perm_setlocale(int category, const char *locale);
 
-extern bool lc_collate_is_c(Oid collation);
 extern bool lc_ctype_is_c(Oid collation);
 
 /*