Don't throw an error for LOCK TABLE on a self-referential view.

LOCK TABLE has complained about "infinite recursion" when applied
to a self-referential view, ever since we made it recurse into views
in v11.  However, that breaks pg_dump's new assumption that it's
okay to lock every relation.  There doesn't seem to be any good
reason to throw an error: if we just abandon the recursion, we've
still satisfied the requirement of locking every referenced relation.

Per bug #16703 from Andrew Bille (via Alexander Lakhin).

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

diff --git a/src/backend/commands/lockcmds.c b/src/backend/commands/lockcmds.c
index f64246dba3917eacc4b4b0b8271fc22262561e08..0cd762ea5b4a14e91ab29385903b26d14c214605 100644 (file)
--- a/src/backend/commands/lockcmds.c
+++ b/src/backend/commands/lockcmds.c
@@ -32,7 +32,8 @@ static void LockTableRecurse(Oid reloid, LOCKMODE lockmode, bool nowait);
 static AclResult LockTableAclCheck(Oid relid, LOCKMODE lockmode, Oid userid);
 static void RangeVarCallbackForLockTable(const RangeVar *rv, Oid relid,
                                         Oid oldrelid, void *arg);
-static void LockViewRecurse(Oid reloid, LOCKMODE lockmode, bool nowait, List *ancestor_views);
+static void LockViewRecurse(Oid reloid, LOCKMODE lockmode, bool nowait,
+                           List *ancestor_views);
 
 /*
  * LOCK TABLE
@@ -195,12 +196,12 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
                 strcmp(rte->eref->aliasname, "new") == 0))
                continue;
 
-           /* Check infinite recursion in the view definition. */
+           /*
+            * We might be dealing with a self-referential view.  If so, we
+            * can just stop recursing, since we already locked it.
+            */
            if (list_member_oid(context->ancestor_views, relid))
-               ereport(ERROR,
-                       (errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
-                        errmsg("infinite recursion detected in rules for relation \"%s\"",
-                               get_rel_name(relid))));
+               continue;
 
            /* Check permissions with the view owner's privilege. */
            aclresult = LockTableAclCheck(relid, context->lockmode, context->viewowner);
@@ -218,7 +219,8 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
                                get_rel_name(relid))));
 
            if (rte->relkind == RELKIND_VIEW)
-               LockViewRecurse(relid, context->lockmode, context->nowait, context->ancestor_views);
+               LockViewRecurse(relid, context->lockmode, context->nowait,
+                               context->ancestor_views);
            else if (rte->inh)
                LockTableRecurse(relid, context->lockmode, context->nowait);
        }
@@ -235,13 +237,14 @@ LockViewRecurse_walker(Node *node, LockViewRecurse_context *context)
 }
 
 static void
-LockViewRecurse(Oid reloid, LOCKMODE lockmode, bool nowait, List *ancestor_views)
+LockViewRecurse(Oid reloid, LOCKMODE lockmode, bool nowait,
+               List *ancestor_views)
 {
    LockViewRecurse_context context;
-
    Relation    view;
    Query      *viewquery;
 
+   /* caller has already locked the view */
    view = table_open(reloid, NoLock);
    viewquery = get_view_query(view);
 

diff --git a/src/test/regress/expected/lock.out b/src/test/regress/expected/lock.out
index 1d6a4e9f1e0009d1553683f55375138f5f401b8e..f39280a4fa63a84c9484a3acd60344d871a08548 100644 (file)
--- a/src/test/regress/expected/lock.out
+++ b/src/test/regress/expected/lock.out
@@ -124,16 +124,14 @@ select relname from pg_locks l, pg_class c
 (2 rows)
 
 ROLLBACK;
--- detecting infinite recursions in view definitions
+-- Verify that we cope with infinite recursion in view definitions.
 CREATE OR REPLACE VIEW lock_view2 AS SELECT * from lock_view3;
 BEGIN TRANSACTION;
 LOCK TABLE lock_view2 IN EXCLUSIVE MODE;
-ERROR:  infinite recursion detected in rules for relation "lock_view2"
 ROLLBACK;
 CREATE VIEW lock_view7 AS SELECT * from lock_view2;
 BEGIN TRANSACTION;
 LOCK TABLE lock_view7 IN EXCLUSIVE MODE;
-ERROR:  infinite recursion detected in rules for relation "lock_view2"
 ROLLBACK;
 -- Verify that we can lock a table with inheritance children.
 CREATE TABLE lock_tbl2 (b BIGINT) INHERITS (lock_tbl1);

diff --git a/src/test/regress/sql/lock.sql b/src/test/regress/sql/lock.sql
index 98d13fc8e1e8364298d28d31366d26a446716700..4f032f1c2e4f2c49e658ec995314c5139c9454d1 100644 (file)
--- a/src/test/regress/sql/lock.sql
+++ b/src/test/regress/sql/lock.sql
@@ -87,7 +87,7 @@ select relname from pg_locks l, pg_class c
  where l.relation = c.oid and relname like '%lock_%' and mode = 'ExclusiveLock'
  order by relname;
 ROLLBACK;
--- detecting infinite recursions in view definitions
+-- Verify that we cope with infinite recursion in view definitions.
 CREATE OR REPLACE VIEW lock_view2 AS SELECT * from lock_view3;
 BEGIN TRANSACTION;
 LOCK TABLE lock_view2 IN EXCLUSIVE MODE;