0002-allow-UNLISTEN-during-recovery.patch

From 8c816354e820bf3d0be69d55dbf0052b1d27feeb Mon Sep 17 00:00:00 2001
From: Shay Rojansky <roji@roji.org>
Date: Tue, 15 Jan 2019 18:49:40 +0100
Subject: [PATCH] Allow unlisten when in hot standby:wq

---
 doc/src/sgml/high-availability.sgml            | 16 ++++++++++------
 src/backend/tcop/utility.c                     |  2 +-
 src/test/regress/sql/hs_standby_allowed.sql    |  4 ++++
 src/test/regress/sql/hs_standby_disallowed.sql |  2 --
 4 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 4882b20828..bb1c86f73e 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -1767,6 +1767,11 @@ if (!triggered)
        Plugins and extensions - <command>LOAD</command>
       </para>
      </listitem>
+     <listitem>
+      <para>
+       UNLISTEN
+      </para>
+     </listitem>
     </itemizedlist>
    </para>
 
@@ -1856,18 +1861,17 @@ if (!triggered)
      </listitem>
      <listitem>
       <para>
-       <command>LISTEN</command>, <command>UNLISTEN</command>, <command>NOTIFY</command>
+       <command>LISTEN</command>, <command>NOTIFY</command>
       </para>
      </listitem>
     </itemizedlist>
    </para>
 
    <para>
-    In normal operation, <quote>read-only</quote> transactions are allowed to
-    use <command>LISTEN</command>, <command>UNLISTEN</command>, and
-    <command>NOTIFY</command>, so Hot Standby sessions operate under slightly tighter
-    restrictions than ordinary read-only sessions.  It is possible that some
-    of these restrictions might be loosened in a future release.
+    In normal operation, <quote>read-only</quote> transactions are allowed to use
+    <command>LISTEN</command>, and <command>NOTIFY</command>, so Hot Standby sessions
+    operate under slightly tighter restrictions than ordinary read-only sessions.
+    It is possible that some of these restrictions might be loosened in a future release.
    </para>
 
    <para>
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 27ae6be751..44136060d6 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -629,7 +629,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 			{
 				UnlistenStmt *stmt = (UnlistenStmt *) parsetree;
 
-				PreventCommandDuringRecovery("UNLISTEN");
+				/* allow UNLISTEN during recovery, which is a noop */
 				CheckRestrictedOperation("UNLISTEN");
 				if (stmt->conditionname)
 					Async_Unlisten(stmt->conditionname);
diff --git a/src/test/regress/sql/hs_standby_allowed.sql b/src/test/regress/sql/hs_standby_allowed.sql
index a33199dbbd..1f1cdf5a00 100644
--- a/src/test/regress/sql/hs_standby_allowed.sql
+++ b/src/test/regress/sql/hs_standby_allowed.sql
@@ -110,6 +110,10 @@ LOCK hs1 IN ROW SHARE MODE;
 LOCK hs1 IN ROW EXCLUSIVE MODE;
 COMMIT;
 
+-- UNLISTEN
+unlisten a;
+unlisten *;
+
 -- LOAD
 -- should work, easier if there is no test for that...
 
diff --git a/src/test/regress/sql/hs_standby_disallowed.sql b/src/test/regress/sql/hs_standby_disallowed.sql
index 21bbf526b7..a470600eec 100644
--- a/src/test/regress/sql/hs_standby_disallowed.sql
+++ b/src/test/regress/sql/hs_standby_disallowed.sql
@@ -88,8 +88,6 @@ COMMIT;
 -- Listen
 listen a;
 notify a;
-unlisten a;
-unlisten *;
 
 -- disallowed commands
 
-- 
2.19.1