Implement type regcollation

This will be helpful for a following commit and it's also just
generally useful, like the other reg* types.

Author: Julien Rouhaud
Reviewed-by: Thomas Munro and Michael Paquier
Discussion: https://postgr.es/m/CAEepm%3D0uEQCpfq_%2BLYFBdArCe4Ot98t1aR4eYiYTe%3DyavQygiQ%40mail.gmail.com

3 files changed, 22 insertions, 2 deletions

diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index 157fe4e7275..b9c5214ab8b 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -4477,6 +4477,10 @@ INSERT INTO mytable VALUES(-1);  -- fails
    </indexterm>
 
    <indexterm zone="datatype-oid">
+    <primary>regcollation</primary>
+   </indexterm>
+
+   <indexterm zone="datatype-oid">
     <primary>regconfig</primary>
    </indexterm>
 
@@ -4602,6 +4606,12 @@ SELECT * FROM pg_attribute
         <entry><literal>pg_type</literal></entry>
        </row>
 
+       <row>
+        <entry><type>regcollation</type></entry>
+        <entry><structname>pg_collation</structname></entry>
+        <entry>collation name</entry>
+        <entry><literal>"POSIX"</literal></entry>
+       </row>
 
        <row>
         <entry><type>regconfig</type></entry>
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2a8683a7347..464a48ed6af 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -18178,6 +18178,10 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
    </indexterm>
 
    <indexterm>
+    <primary>to_regcollation</primary>
+   </indexterm>
+
+   <indexterm>
     <primary>to_regnamespace</primary>
    </indexterm>
 
@@ -18390,6 +18394,11 @@ SELECT pg_type_is_visible('myschema.widget'::regtype);
        <entry>get the OID of the named relation</entry>
       </row>
       <row>
+       <entry><literal><function>to_regcollation(<parameter>coll_name</parameter>)</function></literal></entry>
+       <entry><type>regcollation</type></entry>
+       <entry>get the OID of the named collation</entry>
+      </row>
+      <row>
        <entry><literal><function>to_regnamespace(<parameter>schema_name</parameter>)</function></literal></entry>
        <entry><type>regnamespace</type></entry>
        <entry>get the OID of the named schema</entry>
@@ -18720,11 +18729,11 @@ SELECT collation for ('foo' COLLATE "de_DE");
   </para>
 
   <para>
-   The functions <function>to_regclass</function>,
+   The functions <function>to_regclass</function>, <function>to_regcollation</function>,
    <function>to_regnamespace</function>, <function>to_regoper</function>,
    <function>to_regoperator</function>, <function>to_regrole</function>,
    <function>to_regproc</function>, <function>to_regprocedure</function>, and
-   <function>to_regtype</function>, functions translate relation, schema,
+   <function>to_regtype</function>, functions translate relation, collation, schema,
    operator, role, function, and type names (given as <type>text</type>) to
    objects of the corresponding <type>reg*</type> type (see <xref
    linkend="datatype-oid"/> about the types).  These functions differ from a
diff --git a/doc/src/sgml/ref/pgupgrade.sgml b/doc/src/sgml/ref/pgupgrade.sgml
index 9e4b2d69a4d..49de1d57ab2 100644
--- a/doc/src/sgml/ref/pgupgrade.sgml
+++ b/doc/src/sgml/ref/pgupgrade.sgml
@@ -774,6 +774,7 @@ psql --username=postgres --file=script.sql postgres
    <application>pg_upgrade</application> does not support upgrading of databases
    containing table columns using these <type>reg*</type> OID-referencing system data types:
    <simplelist>
+    <member><type>regcollation</type></member>
     <member><type>regconfig</type></member>
     <member><type>regdictionary</type></member>
     <member><type>regnamespace</type></member>