Don't show unusable collations in psql's \dO command.

"Unusable" collations are those not matching the current database's
encoding.  The former behavior inconsistently showed such collations
some of the time, depending on the details of the pattern argument.

diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 24e8ee0a368394cf24fa51f0a4795efffe2830cb..ac351d32d429c6fc266ec0f96e60e77b2ebc017f 100644 (file)
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -1264,7 +1264,7 @@ testdb=>
         <term><literal>\dL[S+] [ <link linkend="APP-PSQL-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
         <listitem>
         <para>
-        Lists all procedural languages. If <replaceable
+        Lists procedural languages. If <replaceable
         class="parameter">pattern</replaceable>
         is specified, only languages whose names match the pattern are listed.
         By default, only user-created languages
@@ -1311,7 +1311,6 @@ testdb=&gt;
 
       <varlistentry>
         <term><literal>\dO[S+] [ <link linkend="APP-PSQL-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
-
         <listitem>
         <para>
         Lists collations.
@@ -1320,8 +1319,11 @@ testdb=&gt;
         listed.  By default, only user-created objects are shown;
         supply a pattern or the <literal>S</literal> modifier to
         include system objects.  If <literal>+</literal> is appended
-        to the command name, each object is listed with its associated
+        to the command name, each collation is listed with its associated
         description, if any.
+        Note that only collations usable with the current database's encoding
+        are shown, so the results may vary in different databases of the
+        same installation.
         </para>
         </listitem>
       </varlistentry>

diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 09a40093d1f6789cf2b2aa0da4e53751b06e7936..a30eaeb10f6faef44062c06a1bd4da87a2ad8a7e 100644 (file)
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2883,7 +2883,7 @@ listCasts(const char *pattern)
 /*
  * \dO
  *
- * Describes collations
+ * Describes collations.
  */
 bool
 listCollations(const char *pattern, bool verbose, bool showSystem)
@@ -2907,17 +2907,25 @@ listCollations(const char *pattern, bool verbose, bool showSystem)
 
        if (verbose)
                appendPQExpBuffer(&buf,
-                 ",\n  pg_catalog.obj_description(c.oid, 'pg_collation') AS \"%s\"",
+                 ",\n       pg_catalog.obj_description(c.oid, 'pg_collation') AS \"%s\"",
                                                  gettext_noop("Description"));
 
        appendPQExpBuffer(&buf,
-                                         "FROM pg_catalog.pg_collation c, pg_catalog.pg_namespace n\n"
+                                         "\nFROM pg_catalog.pg_collation c, pg_catalog.pg_namespace n\n"
                                          "WHERE n.oid = c.collnamespace\n");
 
        if (!showSystem && !pattern)
                appendPQExpBuffer(&buf, "      AND n.nspname <> 'pg_catalog'\n"
                                                  "      AND n.nspname <> 'information_schema'\n");
 
+       /*
+        * Hide collations that aren't usable in the current database's encoding.
+        * If you think to change this, note that pg_collation_is_visible rejects
+        * unusable collations, so you will need to hack name pattern processing
+        * somehow to avoid inconsistent behavior.
+        */
+       appendPQExpBuffer(&buf, "      AND c.collencoding IN (-1, pg_catalog.pg_char_to_encoding(pg_catalog.getdatabaseencoding()))\n");
+
        processSQLNamePattern(pset.db, &buf, pattern, true, false,
                                                  "n.nspname", "c.collname", NULL,
                                                  "pg_catalog.pg_collation_is_visible(c.oid)");