Revert "Accept relations of any kind in LOCK TABLE".

Revert 59ab4ac32, as well as the followup fix 33862cb9c, in all
branches.  We need to think a bit harder about what the behavior
of LOCK TABLE on views should be, and there's no time for that
before next week's releases.  We'll take another crack at this
later.

Discussion: https://postgr.es/m/16703-e348f58aab3cf6cc@postgresql.org

4 files changed, 20 insertions, 44 deletions

diff --git a/doc/src/sgml/ref/lock.sgml b/doc/src/sgml/ref/lock.sgml
index 9b33ddc637..b946eab303 100644
--- a/doc/src/sgml/ref/lock.sgml
+++ b/doc/src/sgml/ref/lock.sgml
@@ -16,7 +16,7 @@ PostgreSQL documentation
 
  <refnamediv>
   <refname>LOCK</refname>
-  <refpurpose>lock a named relation (table, etc)</refpurpose>
+  <refpurpose>lock a table</refpurpose>
  </refnamediv>
 
  <refsynopsisdiv>
@@ -34,9 +34,7 @@ LOCK [ TABLE ] [ ONLY ] <replaceable class="PARAMETER">name</replaceable> [ * ]
   <title>Description</title>
 
   <para>
-   <command>LOCK TABLE</command> obtains a table-level lock on a
-   relation (table, partitioned table, foreign table, view,
-   materialized view, index, composite type, sequence), waiting
+   <command>LOCK TABLE</command> obtains a table-level lock, waiting
    if necessary for any conflicting locks to be released.  If
    <literal>NOWAIT</literal> is specified, <command>LOCK
    TABLE</command> does not wait to acquire the desired lock: if it
@@ -112,23 +110,17 @@ LOCK [ TABLE ] [ ONLY ] <replaceable class="PARAMETER">name</replaceable> [ * ]
     <term><replaceable class="PARAMETER">name</replaceable></term>
     <listitem>
      <para>
-      The name (optionally schema-qualified) of an existing relation to
-      lock. If <literal>ONLY</literal> is specified before a table name, only that
-      table is locked. If <literal>ONLY</literal> is not specified, the table and all
-      its descendant tables (if any) are locked.  Optionally, <literal>*</literal>
+      The name (optionally schema-qualified) of an existing table to
+      lock. If <literal>ONLY</> is specified before the table name, only that
+      table is locked. If <literal>ONLY</> is not specified, the table and all
+      its descendant tables (if any) are locked.  Optionally, <literal>*</>
       can be specified after the table name to explicitly indicate that
       descendant tables are included.
      </para>
 
      <para>
-      Locking a view locks only the view object itself, not any referenced
-      relations.  (Note that this behavior is different
-      in <productname>PostgreSQL</productname> v11 and later.)
-     </para>
-
-     <para>
-      The command <literal>LOCK TABLE a, b;</literal> is equivalent to
-      <literal>LOCK TABLE a; LOCK TABLE b;</literal>. The relations are locked
+      The command <literal>LOCK TABLE a, b;</> is equivalent to
+      <literal>LOCK TABLE a; LOCK TABLE b;</>. The tables are locked
       one-by-one in the order specified in the <command>LOCK
       TABLE</command> command.
      </para>
diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index 15b4c2f90a..a1670821aa 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -87,6 +87,13 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 		return;					/* woops, concurrently dropped; no permissions
 								 * check */
 
+	/* Currently, we only allow plain tables to be locked */
+	if (relkind != RELKIND_RELATION)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("\"%s\" is not a table",
+						rv->relname)));
+
 	/* Check permissions. */
 	aclresult = LockTableAclCheck(relid, lockmode);
 	if (aclresult != ACLCHECK_OK)
diff --git a/src/test/regress/expected/lock.out b/src/test/regress/expected/lock.out
index fec1c37983..fd27344503 100644
--- a/src/test/regress/expected/lock.out
+++ b/src/test/regress/expected/lock.out
@@ -5,10 +5,7 @@
 CREATE SCHEMA lock_schema1;
 SET search_path = lock_schema1;
 CREATE TABLE lock_tbl1 (a BIGINT);
-CREATE VIEW lock_view1 AS SELECT 1 AS a;
-CREATE MATERIALIZED VIEW lock_mv1 AS SELECT * FROM lock_view1;
-CREATE INDEX lock_mvi1 ON lock_mv1 (a);
-CREATE SEQUENCE lock_seq;
+CREATE VIEW lock_view1 AS SELECT 1;
 CREATE ROLE regress_rol_lock1;
 ALTER ROLE regress_rol_lock1 SET search_path = lock_schema1;
 GRANT USAGE ON SCHEMA lock_schema1 TO regress_rol_lock1;
@@ -33,7 +30,8 @@ LOCK TABLE lock_tbl1 IN SHARE MODE NOWAIT;
 LOCK TABLE lock_tbl1 IN SHARE ROW EXCLUSIVE MODE NOWAIT;
 LOCK TABLE lock_tbl1 IN EXCLUSIVE MODE NOWAIT;
 LOCK TABLE lock_tbl1 IN ACCESS EXCLUSIVE MODE NOWAIT;
-LOCK TABLE lock_view1 IN EXCLUSIVE MODE;
+LOCK TABLE lock_view1 IN EXCLUSIVE MODE;   -- Will fail; can't lock a non-table
+ERROR:  "lock_view1" is not a table
 ROLLBACK;
 -- Verify that we can lock a table with inheritance children.
 CREATE TABLE lock_tbl2 (b BIGINT) INHERITS (lock_tbl1);
@@ -53,21 +51,13 @@ BEGIN;
 LOCK TABLE ONLY lock_tbl1;
 ROLLBACK;
 RESET ROLE;
--- Lock other relations
-BEGIN TRANSACTION;
-LOCK TABLE lock_mv1;
-LOCK TABLE lock_mvi1;
-LOCK TABLE lock_seq;
-ROLLBACK;
 --
 -- Clean up
 --
-DROP MATERIALIZED VIEW lock_mv1;
 DROP VIEW lock_view1;
 DROP TABLE lock_tbl3;
 DROP TABLE lock_tbl2;
 DROP TABLE lock_tbl1;
-DROP SEQUENCE lock_seq;
 DROP SCHEMA lock_schema1 CASCADE;
 DROP ROLE regress_rol_lock1;
 -- atomic ops tests
diff --git a/src/test/regress/sql/lock.sql b/src/test/regress/sql/lock.sql
index 81af5d08fc..567e8bccf1 100644
--- a/src/test/regress/sql/lock.sql
+++ b/src/test/regress/sql/lock.sql
@@ -6,10 +6,7 @@
 CREATE SCHEMA lock_schema1;
 SET search_path = lock_schema1;
 CREATE TABLE lock_tbl1 (a BIGINT);
-CREATE VIEW lock_view1 AS SELECT 1 AS a;
-CREATE MATERIALIZED VIEW lock_mv1 AS SELECT * FROM lock_view1;
-CREATE INDEX lock_mvi1 ON lock_mv1 (a);
-CREATE SEQUENCE lock_seq;
+CREATE VIEW lock_view1 AS SELECT 1;
 CREATE ROLE regress_rol_lock1;
 ALTER ROLE regress_rol_lock1 SET search_path = lock_schema1;
 GRANT USAGE ON SCHEMA lock_schema1 TO regress_rol_lock1;
@@ -36,7 +33,7 @@ LOCK TABLE lock_tbl1 IN SHARE MODE NOWAIT;
 LOCK TABLE lock_tbl1 IN SHARE ROW EXCLUSIVE MODE NOWAIT;
 LOCK TABLE lock_tbl1 IN EXCLUSIVE MODE NOWAIT;
 LOCK TABLE lock_tbl1 IN ACCESS EXCLUSIVE MODE NOWAIT;
-LOCK TABLE lock_view1 IN EXCLUSIVE MODE;
+LOCK TABLE lock_view1 IN EXCLUSIVE MODE;   -- Will fail; can't lock a non-table
 ROLLBACK;
 
 -- Verify that we can lock a table with inheritance children.
@@ -58,23 +55,13 @@ LOCK TABLE ONLY lock_tbl1;
 ROLLBACK;
 RESET ROLE;
 
--- Lock other relations
-BEGIN TRANSACTION;
-LOCK TABLE lock_mv1;
-LOCK TABLE lock_mvi1;
-LOCK TABLE lock_seq;
-ROLLBACK;
-
-
 --
 -- Clean up
 --
-DROP MATERIALIZED VIEW lock_mv1;
 DROP VIEW lock_view1;
 DROP TABLE lock_tbl3;
 DROP TABLE lock_tbl2;
 DROP TABLE lock_tbl1;
-DROP SEQUENCE lock_seq;
 DROP SCHEMA lock_schema1 CASCADE;
 DROP ROLE regress_rol_lock1;