From 31b15fe8dcd2e026afc0b566f50141ae9a7273b5 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Tue, 4 Nov 2008 00:57:19 +0000
Subject: [PATCH] =?UTF-8?q?Disallow=20LOCK=20TABLE=20outside=20a=20transac?=
=?UTF-8?q?tion=20block=20(or=20function),=20since=20this=20case=20almost?=
=?UTF-8?q?=20certainly=20represents=20user=20error.=20=20Per=20a=20gripe?=
=?UTF-8?q?=20from=20Sebastian=20B=C3=B6hm=20and=20subsequent=20discussion?=
=?UTF-8?q?.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
---
doc/src/sgml/ref/declare.sgml | 7 +++----
doc/src/sgml/ref/lock.sgml | 17 ++++++++++-------
src/backend/tcop/utility.c | 7 ++++++-
src/test/regress/expected/privileges.out | 6 ++++++
src/test/regress/sql/privileges.sql | 6 ++++++
5 files changed, 31 insertions(+), 12 deletions(-)
diff --git a/doc/src/sgml/ref/declare.sgml b/doc/src/sgml/ref/declare.sgml
index 269d2c101c4..744cda77726 100644
--- a/doc/src/sgml/ref/declare.sgml
+++ b/doc/src/sgml/ref/declare.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/declare.sgml,v 1.42 2007/10/24 23:27:07 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/declare.sgml,v 1.43 2008/11/04 00:57:19 tgl Exp $
PostgreSQL documentation
-->
@@ -175,10 +175,9 @@ DECLARE <replaceable class="parameter">name</replaceable> [ BINARY ] [ INSENSITI
<productname>PostgreSQL</productname> reports an error if such a
command is used outside a transaction block.
Use
- <xref linkend="sql-begin" endterm="sql-begin-title">,
+ <xref linkend="sql-begin" endterm="sql-begin-title"> and
<xref linkend="sql-commit" endterm="sql-commit-title">
- and
- <xref linkend="sql-rollback" endterm="sql-rollback-title">
+ (or <xref linkend="sql-rollback" endterm="sql-rollback-title">)
to define a transaction block.
</para>
diff --git a/doc/src/sgml/ref/lock.sgml b/doc/src/sgml/ref/lock.sgml
index d32e6d364c8..701c2a19a48 100644
--- a/doc/src/sgml/ref/lock.sgml
+++ b/doc/src/sgml/ref/lock.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/lock.sgml,v 1.49 2008/09/08 00:47:40 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/lock.sgml,v 1.50 2008/11/04 00:57:19 tgl Exp $
PostgreSQL documentation
-->
@@ -160,12 +160,15 @@ where <replaceable class="PARAMETER">lockmode</replaceable> is one of:
</para>
<para>
- <command>LOCK TABLE</command> is useful only inside a transaction
- block (<command>BEGIN</>/<command>COMMIT</> pair), since the lock
- is dropped as soon as the transaction ends. A <command>LOCK
- TABLE</> command appearing outside any transaction block forms a
- self-contained transaction, so the lock will be dropped as soon as
- it is obtained.
+ <command>LOCK TABLE</> is useless outside a transaction block: the lock
+ would remain held only to the completion of the statement. Therefore
+ <productname>PostgreSQL</productname> reports an error if <command>LOCK</>
+ is used outside a transaction block.
+ Use
+ <xref linkend="sql-begin" endterm="sql-begin-title"> and
+ <xref linkend="sql-commit" endterm="sql-commit-title">
+ (or <xref linkend="sql-rollback" endterm="sql-rollback-title">)
+ to define a transaction block.
</para>
<para>
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index b1a0fe28ca5..1218e7cb9b8 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.299 2008/10/10 13:48:05 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/tcop/utility.c,v 1.300 2008/11/04 00:57:19 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -938,6 +938,11 @@ ProcessUtility(Node *parsetree,
break;
case T_LockStmt:
+ /*
+ * Since the lock would just get dropped immediately, LOCK TABLE
+ * outside a transaction block is presumed to be user error.
+ */
+ RequireTransactionChain(isTopLevel, "LOCK TABLE");
LockTableCommand((LockStmt *) parsetree);
break;
diff --git a/src/test/regress/expected/privileges.out b/src/test/regress/expected/privileges.out
index 21f9fc26fd9..d1767e95ad4 100644
--- a/src/test/regress/expected/privileges.out
+++ b/src/test/regress/expected/privileges.out
@@ -45,7 +45,9 @@ INSERT INTO atest1 VALUES (1, 'one');
DELETE FROM atest1;
UPDATE atest1 SET a = 1 WHERE b = 'blech';
TRUNCATE atest1;
+BEGIN;
LOCK atest1 IN ACCESS EXCLUSIVE MODE;
+COMMIT;
REVOKE ALL ON atest1 FROM PUBLIC;
SELECT * FROM atest1;
a | b
@@ -102,8 +104,10 @@ DELETE FROM atest2; -- fail
ERROR: permission denied for relation atest2
TRUNCATE atest2; -- fail
ERROR: permission denied for relation atest2
+BEGIN;
LOCK atest2 IN ACCESS EXCLUSIVE MODE; -- fail
ERROR: permission denied for relation atest2
+COMMIT;
COPY atest2 FROM stdin; -- fail
ERROR: permission denied for relation atest2
GRANT ALL ON atest1 TO PUBLIC; -- fail
@@ -155,7 +159,9 @@ DELETE FROM atest2; -- fail
ERROR: permission denied for relation atest2
TRUNCATE atest2; -- fail
ERROR: permission denied for relation atest2
+BEGIN;
LOCK atest2 IN ACCESS EXCLUSIVE MODE; -- ok
+COMMIT;
COPY atest2 FROM stdin; -- fail
ERROR: permission denied for relation atest2
-- checks in subquery, both fail
diff --git a/src/test/regress/sql/privileges.sql b/src/test/regress/sql/privileges.sql
index 450d5d9d68d..63532f7e095 100644
--- a/src/test/regress/sql/privileges.sql
+++ b/src/test/regress/sql/privileges.sql
@@ -48,7 +48,9 @@ INSERT INTO atest1 VALUES (1, 'one');
DELETE FROM atest1;
UPDATE atest1 SET a = 1 WHERE b = 'blech';
TRUNCATE atest1;
+BEGIN;
LOCK atest1 IN ACCESS EXCLUSIVE MODE;
+COMMIT;
REVOKE ALL ON atest1 FROM PUBLIC;
SELECT * FROM atest1;
@@ -80,7 +82,9 @@ SELECT * FROM atest1 FOR UPDATE; -- ok
SELECT * FROM atest2 FOR UPDATE; -- fail
DELETE FROM atest2; -- fail
TRUNCATE atest2; -- fail
+BEGIN;
LOCK atest2 IN ACCESS EXCLUSIVE MODE; -- fail
+COMMIT;
COPY atest2 FROM stdin; -- fail
GRANT ALL ON atest1 TO PUBLIC; -- fail
@@ -105,7 +109,9 @@ SELECT * FROM atest1 FOR UPDATE; -- fail
SELECT * FROM atest2 FOR UPDATE; -- fail
DELETE FROM atest2; -- fail
TRUNCATE atest2; -- fail
+BEGIN;
LOCK atest2 IN ACCESS EXCLUSIVE MODE; -- ok
+COMMIT;
COPY atest2 FROM stdin; -- fail
-- checks in subquery, both fail
--
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