From a6dcf9df4d91ff0db23579f9114079abe6f3e2bf Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Wed, 17 Apr 2019 09:33:51 +0900
Subject: Rework handling of invalid indexes with REINDEX CONCURRENTLY
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Per discussion with others, allowing REINDEX INDEX CONCURRENTLY to work
for invalid indexes when working directly on them can have a lot of
value to unlock situations with invalid indexes without having to use a
dance involving DROP INDEX followed by an extra CREATE INDEX
CONCURRENTLY (which would not work for indexes with constraint
dependency anyway).  This also does not create extra bloat on the
relation involved as this works on individual indexes, so let's enable
it.

Note that REINDEX TABLE CONCURRENTLY still bypasses invalid indexes as
we don't want to bloat the number of indexes defined on a relation in
the event of multiple and successive failures of REINDEX CONCURRENTLY.

More regression tests are added to cover those behaviors, using an
invalid index created with CREATE INDEX CONCURRENTLY.

Reported-by: Dagfinn Ilmari Mannsåker, Álvaro Herrera
Author: Michael Paquier
Reviewed-by: Peter Eisentraut, Dagfinn Ilmari Mannsåker
Discussion: https://postgr.es/m/20190411134947.GA22043@alvherre.pgsql
---
 doc/src/sgml/ref/create_index.sgml |  6 ++----
 doc/src/sgml/ref/reindex.sgml      | 11 +++++------
 2 files changed, 7 insertions(+), 10 deletions(-)

(limited to 'doc/src')

diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index e62ab33905c..521e32b197c 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -586,10 +586,8 @@ Indexes:
 
     The recommended recovery
     method in such cases is to drop the index and try again to perform
-    <command>CREATE INDEX CONCURRENTLY</command>.  (Another possibility is to rebuild
-    the index with <command>REINDEX</command>.  However, since <command>REINDEX</command>
-    does not support concurrent builds, this option is unlikely to seem
-    attractive.)
+    <command>CREATE INDEX CONCURRENTLY</command>.  (Another possibility is
+    to rebuild the index with <command>REINDEX INDEX CONCURRENTLY</command>).
    </para>
 
    <para>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index e05a76c6d88..303436c89db 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -65,12 +65,11 @@ REINDEX [ ( VERBOSE ) ] { INDEX | TABLE | SCHEMA | DATABASE | SYSTEM } [ CONCURR
 
     <listitem>
      <para>
-      An index build with the <literal>CONCURRENTLY</literal> option failed, leaving
-      an <quote>invalid</quote> index. Such indexes are useless but it can be
-      convenient to use <command>REINDEX</command> to rebuild them. Note that
-      <command>REINDEX</command> will not perform a concurrent build on an invalid index. To build the
-      index without interfering with production you should drop the index and
-      reissue the <command>CREATE INDEX CONCURRENTLY</command> command.
+      If an index build fails with the <literal>CONCURRENTLY</literal> option,
+      this index is left as <quote>invalid</quote>. Such indexes are useless
+      but it can be convenient to use <command>REINDEX</command> to rebuild
+      them. Note that only <command>REINDEX INDEX</command> is able
+      to perform a concurrent build on an invalid index.
      </para>
     </listitem>
 
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