Revise REINDEX CONCURRENTLY recovery instructions

When the leftover invalid index is "ccold", there's no need to re-run
the command.  Reword the instructions to make that explicit.

Backpatch to 12, where REINDEX CONCURRENTLY appeared.

Author: Álvaro Herrera 
Reviewed-by: Michael Paquier 
Reviewed-by: Julien Rouhaud 
Discussion: https://postgr.es/m/20200819211312[email protected]

diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index 0ef6125591248d16718999ba7fc1d100628a0708..a8b9a57544b098daba3c1d4a026d17427c263d4d 100644 (file)
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -304,7 +304,7 @@ REINDEX [ ( VERBOSE ) ] { INDEX | TABLE | SCHEMA | DATABASE | SYSTEM } [ CONCURR
     
      
       
-       A new temporary index definition is added to the catalog
+       A new transient index definition is added to the catalog
        pg_index.  This definition will be used to replace
        the old index.  A SHARE UPDATE EXCLUSIVE lock at
        session level is taken on the indexes being reindexed as well as their
@@ -380,13 +380,15 @@ Indexes:
     "idx_ccnew" btree (col) INVALID
 
 
-    The recommended recovery method in such cases is to drop the invalid index
-    and try again to perform REINDEX CONCURRENTLY.  The
-    concurrent index created during the processing has a name ending in the
-    suffix ccnew, or ccold if it is an
-    old index definition which we failed to drop. Invalid indexes can be
-    dropped using DROP INDEX, including invalid toast
-    indexes.
+    If the index marked INVALID is suffixed
+    ccnew, then it corresponds to the transient
+    index created during the concurrent operation, and the recommended
+    recovery method is to drop it using DROP INDEX,
+    then attempt REINDEX CONCURRENTLY again.
+    If the invalid index is instead suffixed ccold,
+    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.