Accept relations of any kind in LOCK TABLE

The restriction that only tables and views can be locked by LOCK TABLE
is quite arbitrary, since the underlying mechanism can lock any relation
type.  Drop the restriction so that programs such as pg_dump can lock
all relations they're interested in, preventing schema changes that
could cause a dump to fail after expending much effort.

Backpatch to 9.5.

Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reported-by: Wells Oliver <wells.oliver@gmail.com>
Discussion: https://postgr.es/m/20201021200659.GA32358@alvherre.pgsql

3 files changed, 33 insertions, 19 deletions

diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index f672bfbdd7e..1be3a0d1edb 100644
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -94,14 +94,6 @@ RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid, Oid oldrelid,
 		return;					/* woops, concurrently dropped; no permissions
 								 * check */
 
-	/* Currently, we only allow plain tables or views to be locked */
-	if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE &&
-		relkind != RELKIND_VIEW)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table or a view",
-						rv->relname)));
-
 	/*
 	 * Make note if a temporary relation has been accessed in this
 	 * transaction.
@@ -208,11 +200,13 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 		foreach(rtable, query->rtable)
 		{
 			RangeTblEntry *rte = lfirst(rtable);
+			Oid			relid;
 			AclResult	aclresult;
 
-			Oid			relid = rte->relid;
-			char		relkind = rte->relkind;
-			char	   *relname = get_rel_name(relid);
+			/* ignore all non-relation RTEs */
+			if (rte->rtekind != RTE_RELATION)
+				continue;
+			relid = rte->relid;
 
 			/*
 			 * The OLD and NEW placeholder entries in the view's rtable are
@@ -222,11 +216,6 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 				(!strcmp(rte->eref->aliasname, "old") || !strcmp(rte->eref->aliasname, "new")))
 				continue;
 
-			/* Currently, we only allow plain tables or views to be locked. */
-			if (relkind != RELKIND_RELATION && relkind != RELKIND_PARTITIONED_TABLE &&
-				relkind != RELKIND_VIEW)
-				continue;
-
 			/* Check infinite recursion in the view definition. */
 			if (list_member_oid(context->ancestor_views, relid))
 				ereport(ERROR,
@@ -237,7 +226,8 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 			/* Check permissions with the view owner's privilege. */
 			aclresult = LockTableAclCheck(relid, context->lockmode, context->viewowner);
 			if (aclresult != ACLCHECK_OK)
-				aclcheck_error(aclresult, get_relkind_objtype(relkind), relname);
+				aclcheck_error(aclresult, get_relkind_objtype(rte->relkind),
+							   get_rel_name(relid));
 
 			/* We have enough rights to lock the relation; do so. */
 			if (!context->nowait)
@@ -246,9 +236,9 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 				ereport(ERROR,
 						(errcode(ERRCODE_LOCK_NOT_AVAILABLE),
 						 errmsg("could not obtain lock on relation \"%s\"",
-								relname)));
+								get_rel_name(relid))));
 
-			if (relkind == RELKIND_VIEW)
+			if (rte->relkind == RELKIND_VIEW)
 				LockViewRecurse(relid, context->lockmode, context->nowait, context->ancestor_views);
 			else if (rte->inh)
 				LockTableRecurse(relid, context->lockmode, context->nowait, context->viewowner);
diff --git a/src/test/regress/expected/lock.out b/src/test/regress/expected/lock.out
index 185fd2f879b..9e719abaae0 100644
--- a/src/test/regress/expected/lock.out
+++ b/src/test/regress/expected/lock.out
@@ -12,6 +12,9 @@ CREATE VIEW lock_view3 AS SELECT * from lock_view2;
 CREATE VIEW lock_view4 AS SELECT (select a from lock_tbl1a limit 1) from lock_tbl1;
 CREATE VIEW lock_view5 AS SELECT * from lock_tbl1 where a in (select * from lock_tbl1a);
 CREATE VIEW lock_view6 AS SELECT * from (select * from lock_tbl1) sub;
+CREATE MATERIALIZED VIEW lock_mv1 AS SELECT * FROM lock_view6;
+CREATE INDEX lock_mvi1 ON lock_mv1 (a);
+CREATE SEQUENCE lock_seq;
 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;
@@ -150,9 +153,16 @@ 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_view7;
 DROP VIEW lock_view6;
 DROP VIEW lock_view5;
@@ -164,6 +174,7 @@ DROP TABLE lock_tbl3;
 DROP TABLE lock_tbl2;
 DROP TABLE lock_tbl1;
 DROP TABLE lock_tbl1a;
+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 26a7e59a136..6cfa5865bc6 100644
--- a/src/test/regress/sql/lock.sql
+++ b/src/test/regress/sql/lock.sql
@@ -13,6 +13,9 @@ CREATE VIEW lock_view3 AS SELECT * from lock_view2;
 CREATE VIEW lock_view4 AS SELECT (select a from lock_tbl1a limit 1) from lock_tbl1;
 CREATE VIEW lock_view5 AS SELECT * from lock_tbl1 where a in (select * from lock_tbl1a);
 CREATE VIEW lock_view6 AS SELECT * from (select * from lock_tbl1) sub;
+CREATE MATERIALIZED VIEW lock_mv1 AS SELECT * FROM lock_view6;
+CREATE INDEX lock_mvi1 ON lock_mv1 (a);
+CREATE SEQUENCE lock_seq;
 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;
@@ -113,9 +116,18 @@ 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_view7;
 DROP VIEW lock_view6;
 DROP VIEW lock_view5;
@@ -126,6 +138,7 @@ DROP TABLE lock_tbl3;
 DROP TABLE lock_tbl2;
 DROP TABLE lock_tbl1;
 DROP TABLE lock_tbl1a;
+DROP SEQUENCE lock_seq;
 DROP SCHEMA lock_schema1 CASCADE;
 DROP ROLE regress_rol_lock1;