postgres.git / summary / log / commit / refs
commit 741ee48900c5bbf970f23d32e49020408e417bdc
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat Jan 26 02:14:31 2019 +0000
First released in: 12.0, 9.4.21, 9.5.16, 9.6.12, 10.7, 11.2
Allow UNLISTEN in hot-standby mode.
Since LISTEN is (still) disallowed, UNLISTEN must be a no-op in a
hot-standby session, and so there's no harm in allowing it. This
change allows client code to not worry about whether it's connected
to a primary or standby server when performing session-state-reset
type activities. (Note that DISCARD ALL, which includes UNLISTEN,
was already allowed, making it inconsistent to reject UNLISTEN.)
Per discussion, back-patch to all supported versions.
Shay Rojansky, reviewed by Mi Tar
Discussion: https://postgr.es/m/CADT4RqCf2gA_TJtPAjnGzkC3ZiexfBZiLmA-mV66e4UyuVv8bA@mail.gmail.com
doc/src/sgml/high-availability.sgml | 11 ++++++++---
src/backend/tcop/utility.c | 2 +-
src/test/regress/expected/hs_standby_allowed.out | 3 +++
src/test/regress/expected/hs_standby_disallowed.out | 4 ----
src/test/regress/sql/hs_standby_allowed.sql | 4 ++++
src/test/regress/sql/hs_standby_disallowed.sql | 2 --
6 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 3f33c39bd29..b9ab8e41d85 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -1633,6 +1633,11 @@ if (!triggered)
Plugins and extensions - <command>LOAD</>
</para>
</listitem>
+ <listitem>
+ <para>
+ <command>UNLISTEN</command>
+ </para>
+ </listitem>
</itemizedlist>
</para>
@@ -1722,7 +1727,7 @@ if (!triggered)
</listitem>
<listitem>
<para>
- <command>LISTEN</>, <command>UNLISTEN</>, <command>NOTIFY</>
+ <command>LISTEN</>, <command>NOTIFY</>
</para>
</listitem>
</itemizedlist>
@@ -1730,8 +1735,8 @@ if (!triggered)
<para>
In normal operation, <quote>read-only</> transactions are allowed to
- use <command>LISTEN</>, <command>UNLISTEN</>, and
- <command>NOTIFY</>, so Hot Standby sessions operate under slightly tighter
+ 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>
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index c41b3506605..1bafd4e84d2 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -619,7 +619,7 @@ standard_ProcessUtility(Node *parsetree,
{
UnlistenStmt *stmt = (UnlistenStmt *) parsetree;
- PreventCommandDuringRecovery("UNLISTEN");
+ /* we allow UNLISTEN during recovery, as it's a noop */
CheckRestrictedOperation("UNLISTEN");
if (stmt->conditionname)
Async_Unlisten(stmt->conditionname);
diff --git a/src/test/regress/expected/hs_standby_allowed.out b/src/test/regress/expected/hs_standby_allowed.out
index c26c9822f63..b2efb4195d9 100644
--- a/src/test/regress/expected/hs_standby_allowed.out
+++ b/src/test/regress/expected/hs_standby_allowed.out
@@ -208,6 +208,9 @@ LOCK hs1 IN ACCESS SHARE MODE;
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...
-- ALLOWED COMMANDS
diff --git a/src/test/regress/expected/hs_standby_disallowed.out b/src/test/regress/expected/hs_standby_disallowed.out
index bc117413ffd..dff0953e9a6 100644
--- a/src/test/regress/expected/hs_standby_disallowed.out
+++ b/src/test/regress/expected/hs_standby_disallowed.out
@@ -118,10 +118,6 @@ listen a;
ERROR: cannot execute LISTEN during recovery
notify a;
ERROR: cannot execute NOTIFY during recovery
-unlisten a;
-ERROR: cannot execute UNLISTEN during recovery
-unlisten *;
-ERROR: cannot execute UNLISTEN during recovery
-- disallowed commands
ANALYZE hs1;
ERROR: cannot execute ANALYZE during recovery
diff --git a/src/test/regress/sql/hs_standby_allowed.sql b/src/test/regress/sql/hs_standby_allowed.sql
index 7fc22148cbc..f15a1a49092 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 21bbf526b74..a470600eec8 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
[parent: fbf5395cb1ea]