Don't install ICU collation keyword variants

Users can still create them themselves.  Instead, document Unicode TR 35
collation options for ICU, so users can create all this themselves.

Reviewed-by: Peter Geoghegan 

diff --git a/doc/src/sgml/charset.sgml b/doc/src/sgml/charset.sgml
index f2a4acc11502bfd34faca05b5f3fd50f810aed15..44e43503a619733e31d55b75e8d542333300758f 100644 (file)
--- a/doc/src/sgml/charset.sgml
+++ b/doc/src/sgml/charset.sgml
@@ -664,13 +664,6 @@ SELECT a COLLATE "C" < b COLLATE "POSIX" FROM test1;
       
      
 
-     
-      de-u-co-phonebk-x-icu
-      
-       German collation, phone book variant
-      
-     
-
      
       de-AT-x-icu
       
@@ -683,13 +676,6 @@ SELECT a COLLATE "C" < b COLLATE "POSIX" FROM test1;
       
      
 
-     
-      de-AT-u-co-phonebk-x-icu
-      
-       German collation for Austria, phone book variant
-      
-     
-
      
       und-x-icu (for undefined)
       
@@ -709,6 +695,90 @@ SELECT a COLLATE "C" < b COLLATE "POSIX" FROM test1;
     will draw an error along the lines of collation "de-x-icu" for
     encoding "WIN874" does not exist.
    
+
+   
+    ICU allows collations to be customized beyond the basic language+country
+    set that is preloaded by initdb.  Users are encouraged
+    to define their own collation objects that make use of these facilities to
+    suit the sorting behavior to their requirements.  Here are some examples:
+
+    
+     
+      CREATE COLLATION "de-u-co-phonebk-x-icu" (provider = icu, locale = 'de-u-co-phonebk')
+      
+       German collation with phone book collation type
+      
+     
+
+     
+      CREATE COLLATION "und-u-co-emoji-x-icu" (provider = icu, locale = 'und-u-co-emoji')
+      
+       
+        Root collation with Emoji collation type, per Unicode Technical Standard #51
+       
+      
+     
+
+     
+      CREATE COLLATION digitslast (provider = icu, locale = 'en-u-kr-latn-digit')
+      
+       
+        Sort digits after Latin letters.  (The default is digits before letters.)
+       
+      
+     
+
+     
+      CREATE COLLATION upperfirst (provider = icu, locale = 'en-u-kf-upper')
+      
+       
+        Sort upper-case letters before lower-case letters.  (The default is
+        lower-case letters first.)
+       
+      
+     
+
+     
+      CREATE COLLATION special (provider = icu, locale = 'en-u-kf-upper-kr-latn-digit')
+      
+       
+        Combines both of the above options.
+       
+      
+     
+
+     
+      CREATE COLLATION numeric (provider = icu, locale = 'en-u-kn-true')
+      
+       
+        Numeric ordering, sorts sequences of digits by their numeric value,
+        for example: A-21 < A-123
+        (also known as natural sort).
+       
+      
+     
+    
+
+    See Unicode
+    Technical Standard #35
+    and BCP 47 for
+    details.  The list of possible collation types (co
+    subtag) can be found in
+    the CLDR
+    repository.
+    The ICU Locale
+    Explorer can be used to check the details of a particular locale
+    definition.
+   
+
+   
+    Note that while this system allows creating collations that ignore
+    case or ignore accents or similar (using
+    the ks key), PostgreSQL does not at the moment allow
+    such collations to act in a truly case- or accent-insensitive manner.  Any
+    strings that compare equal according to the collation but are not
+    byte-wise equal will be sorted according to their byte values.
+   
    
    
 

diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c
index d36ce5356047c9c45a7bf553f78508b68ed09e50..9437731276f67ed49f525ce768ff630d6871bf35 100644 (file)
--- a/src/backend/commands/collationcmds.c
+++ b/src/backend/commands/collationcmds.c
@@ -687,30 +687,11 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
         */
        for (i = -1; i < uloc_countAvailable(); i++)
        {
-           /*
-            * In ICU 4.2, ucol_getKeywordValuesForLocale() sometimes returns
-            * values that will not be accepted by uloc_toLanguageTag().  Skip
-            * loading keyword variants in that version.  (Both
-            * ucol_getKeywordValuesForLocale() and uloc_toLanguageTag() are
-            * new in ICU 4.2, so older versions are not supported at all.)
-            *
-            * XXX We have no information about ICU 4.3 through 4.7, but we
-            * know the code below works with 4.8.
-            */
-#if U_ICU_VERSION_MAJOR_NUM > 4 || (U_ICU_VERSION_MAJOR_NUM == 4 && U_ICU_VERSION_MINOR_NUM > 2)
-#define LOAD_ICU_KEYWORD_VARIANTS
-#endif
-
            const char *name;
            char       *langtag;
            char       *icucomment;
            const char *collcollate;
            Oid         collid;
-#ifdef LOAD_ICU_KEYWORD_VARIANTS
-           UEnumeration *en;
-           UErrorCode  status;
-           const char *val;
-#endif
 
            if (i == -1)
                name = "";      /* ICU root locale */
@@ -744,58 +725,6 @@ pg_import_system_collations(PG_FUNCTION_ARGS)
                    CreateComments(collid, CollationRelationId, 0,
                                   icucomment);
            }
-
-           /*
-            * Add keyword variants, if enabled.
-            */
-#ifdef LOAD_ICU_KEYWORD_VARIANTS
-           status = U_ZERO_ERROR;
-           en = ucol_getKeywordValuesForLocale("collation", name, TRUE, &status);
-           if (U_FAILURE(status))
-               ereport(ERROR,
-                       (errmsg("could not get keyword values for locale \"%s\": %s",
-                               name, u_errorName(status))));
-
-           status = U_ZERO_ERROR;
-           uenum_reset(en, &status);
-           while ((val = uenum_next(en, NULL, &status)))
-           {
-               char       *localeid = psprintf("%s@collation=%s", name, val);
-
-               langtag = get_icu_language_tag(localeid);
-               collcollate = U_ICU_VERSION_MAJOR_NUM >= 54 ? langtag : localeid;
-
-               /*
-                * Be paranoid about not allowing any non-ASCII strings into
-                * pg_collation
-                */
-               if (!is_all_ascii(langtag) || !is_all_ascii(collcollate))
-                   continue;
-
-               collid = CollationCreate(psprintf("%s-x-icu", langtag),
-                                        nspid, GetUserId(),
-                                        COLLPROVIDER_ICU, -1,
-                                        collcollate, collcollate,
-                                        get_collation_actual_version(COLLPROVIDER_ICU, collcollate),
-                                        true, true);
-               if (OidIsValid(collid))
-               {
-                   ncreated++;
-
-                   CommandCounterIncrement();
-
-                   icucomment = get_icu_locale_comment(localeid);
-                   if (icucomment)
-                       CreateComments(collid, CollationRelationId, 0,
-                                      icucomment);
-               }
-           }
-           if (U_FAILURE(status))
-               ereport(ERROR,
-                       (errmsg("could not get keyword values for locale \"%s\": %s",
-                               name, u_errorName(status))));
-           uenum_close(en);
-#endif                         /* LOAD_ICU_KEYWORD_VARIANTS */
        }
    }
 #endif                         /* USE_ICU */