doc: Clarify use of _ccnew and _ccold in REINDEX CONCURRENTLY

Invalid indexes are suffixed with "_ccnew" or "_ccold".  The
documentation missed to mention the initial underscore.
ChooseRelationName() may also append an extra number if indexes with a
similar name already exist; let's add a note about that too.

Author: Alec Cozens <acozens@pixelpower.com>
Discussion: https://postgr.es/m/174733277404.1455388.11471370288789479593@wrigleys.postgresql.org
Backpatch-through: 13

diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index 336ca24b3120ea8d085dbc082d22d4c74e1d4ec0..6b7f6f4eab8aa7a342b33913b5ae22cb232de96c 100644 (file)
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -451,14 +451,17 @@ Indexes:
 </programlisting>
 
     If the index marked <literal>INVALID</literal> is suffixed
-    <literal>ccnew</literal>, then it corresponds to the transient
+    <literal>_ccnew</literal>, then it corresponds to the transient
     index created during the concurrent operation, and the recommended
     recovery method is to drop it using <literal>DROP INDEX</literal>,
     then attempt <command>REINDEX CONCURRENTLY</command> again.
-    If the invalid index is instead suffixed <literal>ccold</literal>,
+    If the invalid index is instead suffixed <literal>_ccold</literal>,
     it corresponds to the original index which could not be dropped;
     the recommended recovery method is to just drop said index, since the
     rebuild proper has been successful.
+    A nonzero number may be appended to the suffix of the invalid index
+    names to keep them unique, like <literal>_ccnew1</literal>,
+    <literal>_ccold2</literal>, etc.
    </para>
 
    <para>