<para>
This example for Unix systems sets the locale to Swedish
(<literal>sv</>) as spoken
- in Sweden (<literal>SE</>). Other possibilities might be
+ in Sweden (<literal>SE</>). Other possibilities might include
<literal>en_US</> (U.S. English) and <literal>fr_CA</> (French
Canadian). If more than one character set can be used for a
locale then the specifications can take the form
<para>
If you want the system to behave as if it had no locale support,
- use the special locale <literal>C</> or <literal>POSIX</>.
+ use the special locale name <literal>C</>, or equivalently
+ <literal>POSIX</>.
</para>
<para>
operator classes exist. These allow the creation of an index that
performs a strict character-by-character comparison, ignoring
locale comparison rules. Refer to <xref linkend="indexes-opclass">
- for more information.
+ for more information. Another approach is to create indexes using
+ the <literal>C</> collation, as discussed in
+ <xref linkend="collation">.
</para>
</sect2>
of a database cannot be changed after its creation.
</para>
- <note>
- <para>
- Collation support is currently only known to work on
- Linux (glibc) and Mac OS X platforms.
- </para>
- </note>
-
<sect2>
<title>Concepts</title>
Conceptually, every expression of a collatable data type has a
collation. (The built-in collatable data types are
<type>text</type>, <type>varchar</type>, and <type>char</type>.
- User-defined base types can also be marked collatable.) If the
+ User-defined base types can also be marked collatable, and of course
+ a domain over a collatable data type is collatable.) If the
expression is a column reference, the collation of the expression is the
defined collation of the column. If the expression is a constant, the
collation is the default collation of the data type of the
<para>
The collation of an expression can be the <quote>default</quote>
collation, which means the locale settings defined for the
- database. In some cases, an expression can also have no known
- collation. In such cases, ordering operations and other
+ database. It is also possible for an expression's collation to be
+ indeterminate. In such cases, ordering operations and other
operations that need to know the collation will fail.
</para>
The <firstterm>collation derivation</firstterm> of an expression can be
implicit or explicit. This distinction affects how collations are
combined when multiple different collations appear in an
- expression. An explicit collation derivation arises when a
+ expression. An explicit collation derivation occurs when a
<literal>COLLATE</literal> clause is used; all other collation
derivations are implicit. When multiple collations need to be
combined, for example in a function call, the following rules are
<listitem>
<para>
Otherwise, all input expressions must have the same implicit
- collation derivation or the default collation. If any
- implicitly derived collation is present, that is the result of
- the collation combination. Otherwise, the result is the
- default collation.
+ collation derivation or the default collation. If any non-default
+ collation is present, that is the result of the collation combination.
+ Otherwise, the result is the default collation.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ If there are conflicting non-default implicit collations among the
+ input expressions, then the combination is deemed to have indeterminate
+ collation. This is not an error condition unless the particular
+ function being invoked requires knowledge of the collation it should
+ apply. If it does, an error will be raised at run-time.
</para>
</listitem>
</orderedlist>
- For example, take this table definition:
+ For example, consider this table definition:
<programlisting>
CREATE TABLE test1 (
- a text COLLATE "x",
+ a text COLLATE "de_DE",
+ b text COLLATE "es_ES",
...
);
</programlisting>
Then in
<programlisting>
-SELECT a || 'foo' FROM test1;
+SELECT a < 'foo' FROM test1;
</programlisting>
- the result collation of the <literal>||</literal> operator is
- <literal>"x"</literal> because it combines an implicitly derived
- collation with the default collation. But in
+ the <literal><</literal> comparison is performed according to
+ <literal>de_DE</literal> rules, because the expression combines an
+ implicitly derived collation with the default collation. But in
<programlisting>
-SELECT a || ('foo' COLLATE "y") FROM test1;
+SELECT a < ('foo' COLLATE "fr_FR") FROM test1;
+</programlisting>
+ the comparison is performed using <literal>fr_FR</literal> rules,
+ because the explicit collation derivation overrides the implicit one.
+ Furthermore, given
+<programlisting>
+SELECT a < b FROM test1;
+</programlisting>
+ the parser cannot determine which collation to apply, since the
+ <structfield>a</> and <structfield>b</> columns have conflicting
+ implicit collations. Since the <literal><</literal> operator
+ does need to know which collation to use, this will result in an
+ error. The error can be resolved by attaching an explicit collation
+ specifier to either input expression, thus:
+<programlisting>
+SELECT a < b COLLATE "de_DE" FROM test1;
+</programlisting>
+ or equivalently
+<programlisting>
+SELECT a COLLATE "de_DE" < b FROM test1;
+</programlisting>
+ On the other hand, the structurally similar case
+<programlisting>
+SELECT a || b FROM test1;
+</programlisting>
+ does not result in an error, because the <literal>||</> operator
+ does not care about collations: its result is the same regardless
+ of the collation.
+ </para>
+
+ <para>
+ The collation assigned to a function or operator's combined input
+ expressions is also considered to apply to the function or operator's
+ result, if the function or operator delivers a result of a collatable
+ data type. So, in
+<programlisting>
+SELECT * FROM test1 ORDER BY a || 'foo';
+</programlisting>
+ the ordering will be done according to <literal>de_DE</literal> rules.
+ But this query:
+<programlisting>
+SELECT * FROM test1 ORDER BY a || b;
+</programlisting>
+ results in an error, because even though the <literal>||</> operator
+ doesn't need to know a collation, the <literal>ORDER BY</> clause does.
+ As before, the conflict can be resolved with an explicit collation
+ specifier:
+<programlisting>
+SELECT * FROM test1 ORDER BY a || b COLLATE "fr_FR";
</programlisting>
- the result collation is <literal>"y"</literal> because the explicit
- collation derivation overrides the implicit one.
</para>
</sect2>
</para>
<para>
- When a database cluster is initialized, <command>initdb</command>
+ On all platforms, the collations named <literal>default</>,
+ <literal>C</>, and <literal>POSIX</> are available. Additional
+ collations may be available depending on operating system support.
+ The <literal>default</> collation selects the <symbol>LC_COLLATE</symbol>
+ and <symbol>LC_CTYPE</symbol> values specified at database creation time.
+ The <literal>C</> and <literal>POSIX</> collations both specify
+ <quote>traditional C</> behavior, in which only the ASCII letters
+ <quote><literal>A</></quote> through <quote><literal>Z</></quote>
+ are treated as letters, and sorting is done strictly by character
+ code byte values.
+ </para>
+
+ <para>
+ If the operating system provides support for using multiple locales
+ within a single program (<function>newlocale</> and related functions),
+ then when a database cluster is initialized, <command>initdb</command>
populates the system catalog <literal>pg_collation</literal> with
collations based on all the locales it finds on the operating
system at the time. For example, the operating system might
within a given database even though it would not be unique globally.
Use of the stripped collation names is recommendable, since it will
make one less thing you need to change if you decide to change to
- another database encoding.
+ another database encoding. Note however that the <literal>default</>,
+ <literal>C</>, and <literal>POSIX</> collations can be used
+ regardless of the database encoding.
+ </para>
+
+ <para>
+ <productname>PostgreSQL</productname> considers distinct collation
+ objects to be incompatible even when they have identical properties.
+ Thus for example,
+<programlisting>
+SELECT a COLLATE "C" < b COLLATE "POSIX" FROM test1;
+</programlisting>
+ will draw an error even though the <literal>C</> and <literal>POSIX</>
+ collations have identical behaviors. Mixing stripped and non-stripped
+ collation names is therefore not recommended.
</para>
</sect2>
</sect1>
* in multibyte character sets. Note that in either case we are effectively
* assuming that the database character encoding matches the encoding implied
* by LC_CTYPE.
+ *
+ * If the system provides locale_t and associated functions (which are
+ * standardized by Open Group's XBD), we can support collations that are
+ * neither default nor C. The code is written to handle both combinations
+ * of have-wide-characters and have-locale_t, though it's rather unlikely
+ * a platform would have the latter without the former.
*/
/*
- * wide-character-aware lower function
+ * collation-aware, wide-character-aware lower function
*
* We pass the number of bytes so we can pass varlena and char*
* to this function. The result is a palloc'd, null-terminated string.
str_tolower(const char *buff, size_t nbytes, Oid collid)
{
char *result;
- pg_locale_t mylocale = 0;
if (!buff)
return NULL;
- if (collid != DEFAULT_COLLATION_OID)
- mylocale = pg_newlocale_from_collation(collid);
+ /* C/POSIX collations use this path regardless of database encoding */
+ if (lc_ctype_is_c(collid))
+ {
+ char *p;
+
+ result = pnstrdup(buff, nbytes);
+ for (p = result; *p; p++)
+ *p = pg_ascii_tolower((unsigned char) *p);
+ }
#ifdef USE_WIDE_UPPER_LOWER
- if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c(collid))
+ else if (pg_database_encoding_max_length() > 1)
{
+ pg_locale_t mylocale = 0;
wchar_t *workspace;
size_t curr_char;
size_t result_size;
+ if (collid != DEFAULT_COLLATION_OID)
+ mylocale = pg_newlocale_from_collation(collid);
+
/* Overflow paranoia */
if ((nbytes + 1) > (INT_MAX / sizeof(wchar_t)))
ereport(ERROR,
char2wchar(workspace, nbytes + 1, buff, nbytes, collid);
for (curr_char = 0; workspace[curr_char] != 0; curr_char++)
+ {
#ifdef HAVE_LOCALE_T
if (mylocale)
workspace[curr_char] = towlower_l(workspace[curr_char], mylocale);
else
#endif
- workspace[curr_char] = towlower(workspace[curr_char]);
+ workspace[curr_char] = towlower(workspace[curr_char]);
+ }
/* Make result large enough; case change might change number of bytes */
result_size = curr_char * pg_database_encoding_max_length() + 1;
wchar2char(result, workspace, result_size, collid);
pfree(workspace);
}
- else
#endif /* USE_WIDE_UPPER_LOWER */
+ else
{
+ pg_locale_t mylocale = 0;
char *p;
+ if (collid != DEFAULT_COLLATION_OID)
+ mylocale = pg_newlocale_from_collation(collid);
+
result = pnstrdup(buff, nbytes);
+ /*
+ * Note: we assume that tolower_l() will not be so broken as to need
+ * an isupper_l() guard test. When using the default collation, we
+ * apply the traditional Postgres behavior that forces ASCII-style
+ * treatment of I/i, but in non-default collations you get exactly
+ * what the collation says.
+ */
for (p = result; *p; p++)
- *p = pg_tolower((unsigned char) *p);
+ {
+#ifdef HAVE_LOCALE_T
+ if (mylocale)
+ *p = tolower_l((unsigned char) *p, mylocale);
+ else
+#endif
+ *p = pg_tolower((unsigned char) *p);
+ }
}
return result;
}
/*
- * wide-character-aware upper function
+ * collation-aware, wide-character-aware upper function
*
* We pass the number of bytes so we can pass varlena and char*
* to this function. The result is a palloc'd, null-terminated string.
str_toupper(const char *buff, size_t nbytes, Oid collid)
{
char *result;
- pg_locale_t mylocale = 0;
if (!buff)
return NULL;
- if (collid != DEFAULT_COLLATION_OID)
- mylocale = pg_newlocale_from_collation(collid);
+ /* C/POSIX collations use this path regardless of database encoding */
+ if (lc_ctype_is_c(collid))
+ {
+ char *p;
+ result = pnstrdup(buff, nbytes);
+
+ for (p = result; *p; p++)
+ *p = pg_ascii_toupper((unsigned char) *p);
+ }
#ifdef USE_WIDE_UPPER_LOWER
- if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c(collid))
+ else if (pg_database_encoding_max_length() > 1)
{
+ pg_locale_t mylocale = 0;
wchar_t *workspace;
size_t curr_char;
size_t result_size;
+ if (collid != DEFAULT_COLLATION_OID)
+ mylocale = pg_newlocale_from_collation(collid);
+
/* Overflow paranoia */
if ((nbytes + 1) > (INT_MAX / sizeof(wchar_t)))
ereport(ERROR,
char2wchar(workspace, nbytes + 1, buff, nbytes, collid);
for (curr_char = 0; workspace[curr_char] != 0; curr_char++)
+ {
#ifdef HAVE_LOCALE_T
if (mylocale)
workspace[curr_char] = towupper_l(workspace[curr_char], mylocale);
else
#endif
- workspace[curr_char] = towupper(workspace[curr_char]);
+ workspace[curr_char] = towupper(workspace[curr_char]);
+ }
/* Make result large enough; case change might change number of bytes */
result_size = curr_char * pg_database_encoding_max_length() + 1;
wchar2char(result, workspace, result_size, collid);
pfree(workspace);
}
- else
#endif /* USE_WIDE_UPPER_LOWER */
+ else
{
+ pg_locale_t mylocale = 0;
char *p;
+ if (collid != DEFAULT_COLLATION_OID)
+ mylocale = pg_newlocale_from_collation(collid);
+
result = pnstrdup(buff, nbytes);
+ /*
+ * Note: we assume that toupper_l() will not be so broken as to need
+ * an islower_l() guard test. When using the default collation, we
+ * apply the traditional Postgres behavior that forces ASCII-style
+ * treatment of I/i, but in non-default collations you get exactly
+ * what the collation says.
+ */
for (p = result; *p; p++)
- *p = pg_toupper((unsigned char) *p);
+ {
+#ifdef HAVE_LOCALE_T
+ if (mylocale)
+ *p = toupper_l((unsigned char) *p, mylocale);
+ else
+#endif
+ *p = pg_toupper((unsigned char) *p);
+ }
}
return result;
}
/*
- * wide-character-aware initcap function
+ * collation-aware, wide-character-aware initcap function
*
* We pass the number of bytes so we can pass varlena and char*
* to this function. The result is a palloc'd, null-terminated string.
{
char *result;
int wasalnum = false;
- pg_locale_t mylocale = 0;
if (!buff)
return NULL;
- if (collid != DEFAULT_COLLATION_OID)
- mylocale = pg_newlocale_from_collation(collid);
+ /* C/POSIX collations use this path regardless of database encoding */
+ if (lc_ctype_is_c(collid))
+ {
+ char *p;
+
+ result = pnstrdup(buff, nbytes);
+ for (p = result; *p; p++)
+ {
+ char c;
+
+ if (wasalnum)
+ *p = c = pg_ascii_tolower((unsigned char) *p);
+ else
+ *p = c = pg_ascii_toupper((unsigned char) *p);
+ /* we don't trust isalnum() here */
+ wasalnum = ((c >= 'A' && c <= 'Z') ||
+ (c >= 'a' && c <= 'z') ||
+ (c >= '0' && c <= '9'));
+ }
+ }
#ifdef USE_WIDE_UPPER_LOWER
- if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c(collid))
+ else if (pg_database_encoding_max_length() > 1)
{
+ pg_locale_t mylocale = 0;
wchar_t *workspace;
size_t curr_char;
size_t result_size;
+ if (collid != DEFAULT_COLLATION_OID)
+ mylocale = pg_newlocale_from_collation(collid);
+
/* Overflow paranoia */
if ((nbytes + 1) > (INT_MAX / sizeof(wchar_t)))
ereport(ERROR,
wchar2char(result, workspace, result_size, collid);
pfree(workspace);
}
- else
#endif /* USE_WIDE_UPPER_LOWER */
+ else
{
+ pg_locale_t mylocale = 0;
char *p;
+ if (collid != DEFAULT_COLLATION_OID)
+ mylocale = pg_newlocale_from_collation(collid);
+
result = pnstrdup(buff, nbytes);
+ /*
+ * Note: we assume that toupper_l()/tolower_l() will not be so broken
+ * as to need guard tests. When using the default collation, we apply
+ * the traditional Postgres behavior that forces ASCII-style treatment
+ * of I/i, but in non-default collations you get exactly what the
+ * collation says.
+ */
for (p = result; *p; p++)
{
- if (wasalnum)
- *p = pg_tolower((unsigned char) *p);
+#ifdef HAVE_LOCALE_T
+ if (mylocale)
+ {
+ if (wasalnum)
+ *p = tolower_l((unsigned char) *p, mylocale);
+ else
+ *p = toupper_l((unsigned char) *p, mylocale);
+ wasalnum = isalnum_l((unsigned char) *p, mylocale);
+ }
else
- *p = pg_toupper((unsigned char) *p);
- wasalnum = isalnum((unsigned char) *p);
+#endif
+ {
+ if (wasalnum)
+ *p = pg_tolower((unsigned char) *p);
+ else
+ *p = pg_toupper((unsigned char) *p);
+ wasalnum = isalnum((unsigned char) *p);
+ }
}
}
static char lc_numeric_envbuf[LC_ENV_BUFSIZE];
static char lc_time_envbuf[LC_ENV_BUFSIZE];
+/* Cache for collation-related knowledge */
+
+typedef struct
+{
+ Oid collid; /* hash key: pg_collation OID */
+ bool collate_is_c; /* is collation's LC_COLLATE C? */
+ bool ctype_is_c; /* is collation's LC_CTYPE C? */
+ bool flags_valid; /* true if above flags are valid */
+ pg_locale_t locale; /* locale_t struct, or 0 if not valid */
+} collation_cache_entry;
+
+static HTAB *collation_cache = NULL;
+
+
#if defined(WIN32) && defined(LC_MESSAGES)
static char *IsoLocaleName(const char *); /* MSVC specific */
#endif
-static HTAB *locale_cness_cache = NULL;
-#ifdef HAVE_LOCALE_T
-static HTAB *locale_t_cache = NULL;
-#endif
-
/*
* pg_perm_setlocale
}
-/*
- * We'd like to cache whether LC_COLLATE or LC_CTYPE is C (or POSIX),
- * so we can optimize a few code paths in various places.
- *
- * Note that some code relies on this not reporting false negatives
- * (that is, saying it's not C when it is). For example, char2wchar()
- * could fail if the locale is C, so str_tolower() shouldn't call it
- * in that case.
- */
-
-struct locale_cness_cache_entry
-{
- Oid collid;
- bool collate_is_c;
- bool ctype_is_c;
-};
-
-static void
-init_locale_cness_cache(void)
-{
- HASHCTL ctl;
-
- memset(&ctl, 0, sizeof(ctl));
- ctl.keysize = sizeof(Oid);
- ctl.entrysize = sizeof(struct locale_cness_cache_entry);
- ctl.hash = oid_hash;
- locale_cness_cache = hash_create("locale C-ness cache", 1000, &ctl, HASH_ELEM | HASH_FUNCTION);
-}
-
-/*
- * Handle caching of locale "C-ness" for nondefault collation objects.
- * Relying on the system cache directly isn't fast enough.
- */
-static bool
-lookup_collation_cness(Oid collation, int category)
-{
- struct locale_cness_cache_entry *cache_entry;
- bool found;
- HeapTuple tp;
- char *localeptr;
-
- Assert(OidIsValid(collation));
- Assert(category == LC_COLLATE || category == LC_CTYPE);
-
- if (!locale_cness_cache)
- init_locale_cness_cache();
-
- cache_entry = hash_search(locale_cness_cache, &collation, HASH_ENTER, &found);
- if (found)
- {
- if (category == LC_COLLATE)
- return cache_entry->collate_is_c;
- else
- return cache_entry->ctype_is_c;
- }
-
- tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(collation));
- if (!HeapTupleIsValid(tp))
- elog(ERROR, "cache lookup failed for collation %u", collation);
-
- localeptr = NameStr(((Form_pg_collation) GETSTRUCT(tp))->collcollate);
- cache_entry->collate_is_c = (strcmp(localeptr, "C") == 0) || (strcmp(localeptr, "POSIX") == 0);
-
- localeptr = NameStr(((Form_pg_collation) GETSTRUCT(tp))->collctype);
- cache_entry->ctype_is_c = (strcmp(localeptr, "C") == 0) || (strcmp(localeptr, "POSIX") == 0);
-
- ReleaseSysCache(tp);
-
- return category == LC_COLLATE ? cache_entry->collate_is_c : cache_entry->ctype_is_c;
-}
-
-
-bool
-lc_collate_is_c(Oid collation)
-{
- /* Cache result so we only have to compute it once */
- static int result = -1;
- char *localeptr;
-
- if (!OidIsValid(collation))
- return false;
-
- if (collation != DEFAULT_COLLATION_OID)
- return lookup_collation_cness(collation, LC_COLLATE);
-
- if (result >= 0)
- return (bool) result;
- localeptr = setlocale(LC_COLLATE, NULL);
- if (!localeptr)
- elog(ERROR, "invalid LC_COLLATE setting");
-
- if (strcmp(localeptr, "C") == 0)
- result = true;
- else if (strcmp(localeptr, "POSIX") == 0)
- result = true;
- else
- result = false;
- return (bool) result;
-}
-
-
-bool
-lc_ctype_is_c(Oid collation)
-{
- /* Cache result so we only have to compute it once */
- static int result = -1;
- char *localeptr;
-
- if (!OidIsValid(collation))
- return false;
-
- if (collation != DEFAULT_COLLATION_OID)
- return lookup_collation_cness(collation, LC_CTYPE);
-
- if (result >= 0)
- return (bool) result;
- localeptr = setlocale(LC_CTYPE, NULL);
- if (!localeptr)
- elog(ERROR, "invalid LC_CTYPE setting");
-
- if (strcmp(localeptr, "C") == 0)
- result = true;
- else if (strcmp(localeptr, "POSIX") == 0)
- result = true;
- else
- result = false;
- return (bool) result;
-}
-
-
/*
* Frees the malloced content of a struct lconv. (But not the struct
* itself.)
#endif /* WIN32 && LC_MESSAGES */
-#ifdef HAVE_LOCALE_T
-struct locale_t_cache_entry
+/*
+ * Cache mechanism for collation information.
+ *
+ * We cache two flags: whether the collation's LC_COLLATE or LC_CTYPE is C
+ * (or POSIX), so we can optimize a few code paths in various places.
+ * For the built-in C and POSIX collations, we can know that without even
+ * doing a cache lookup, but we want to support aliases for C/POSIX too.
+ * For the "default" collation, there are separate static cache variables,
+ * since consulting the pg_collation catalog doesn't tell us what we need.
+ *
+ * Also, if a pg_locale_t has been requested for a collation, we cache that
+ * for the life of a backend.
+ *
+ * Note that some code relies on the flags not reporting false negatives
+ * (that is, saying it's not C when it is). For example, char2wchar()
+ * could fail if the locale is C, so str_tolower() shouldn't call it
+ * in that case.
+ *
+ * Note that we currently lack any way to flush the cache. Since we don't
+ * support ALTER COLLATION, this is OK. The worst case is that someone
+ * drops a collation, and a useless cache entry hangs around in existing
+ * backends.
+ */
+
+static collation_cache_entry *
+lookup_collation_cache(Oid collation, bool set_flags)
{
- Oid collid;
- locale_t locale;
-};
+ collation_cache_entry *cache_entry;
+ bool found;
-static void
-init_locale_t_cache(void)
+ Assert(OidIsValid(collation));
+ Assert(collation != DEFAULT_COLLATION_OID);
+
+ if (collation_cache == NULL)
+ {
+ /* First time through, initialize the hash table */
+ HASHCTL ctl;
+
+ memset(&ctl, 0, sizeof(ctl));
+ ctl.keysize = sizeof(Oid);
+ ctl.entrysize = sizeof(collation_cache_entry);
+ ctl.hash = oid_hash;
+ collation_cache = hash_create("Collation cache", 100, &ctl,
+ HASH_ELEM | HASH_FUNCTION);
+ }
+
+ cache_entry = hash_search(collation_cache, &collation, HASH_ENTER, &found);
+ if (!found)
+ {
+ /*
+ * Make sure cache entry is marked invalid, in case we fail before
+ * setting things.
+ */
+ cache_entry->flags_valid = false;
+ cache_entry->locale = 0;
+ }
+
+ if (set_flags && !cache_entry->flags_valid)
+ {
+ /* Attempt to set the flags */
+ HeapTuple tp;
+ Form_pg_collation collform;
+ const char *collcollate;
+ const char *collctype;
+
+ tp = SearchSysCache1(COLLOID, ObjectIdGetDatum(collation));
+ if (!HeapTupleIsValid(tp))
+ elog(ERROR, "cache lookup failed for collation %u", collation);
+ collform = (Form_pg_collation) GETSTRUCT(tp);
+
+ collcollate = NameStr(collform->collcollate);
+ collctype = NameStr(collform->collctype);
+
+ cache_entry->collate_is_c = ((strcmp(collcollate, "C") == 0) ||
+ (strcmp(collcollate, "POSIX") == 0));
+ cache_entry->ctype_is_c = ((strcmp(collctype, "C") == 0) ||
+ (strcmp(collctype, "POSIX") == 0));
+
+ cache_entry->flags_valid = true;
+
+ ReleaseSysCache(tp);
+ }
+
+ return cache_entry;
+}
+
+
+/*
+ * Detect whether collation's LC_COLLATE property is C
+ */
+bool
+lc_collate_is_c(Oid collation)
{
- HASHCTL ctl;
+ /*
+ * If we're asked about "collation 0", return false, so that the code
+ * will go into the non-C&n
projects / users / c2main / postgres.git / commitdiff