Add CheckTableNotInUse calls in DROP TABLE and DROP INDEX.

Recent releases had a check on rel->rd_refcnt in heap_drop_with_catalog,
but failed to cover the possibility of pending trigger events at DROP time.
(Before 8.4 we didn't even check the refcnt.)  When the trigger events were
eventually fired, you'd get "could not open relation with OID nnn" errors,
as in recent report from strk.  Better to throw a suitable error when the
DROP is attempted.

Also add a similar check in DROP INDEX.

Back-patch to all supported branches.

diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index f4cf829b468100352e6b8c167dbda66a34bc8cee..5dc90660deec2ee0fc6237e10efa2272f0b7b367 100644 (file)
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -1426,14 +1426,10 @@ heap_drop_with_catalog(Oid relid)
 
    /*
     * There can no longer be anyone *else* touching the relation, but we
-    * might still have open queries or cursors in our own session.
+    * might still have open queries or cursors, or pending trigger events,
+    * in our own session.
     */
-   if (rel->rd_refcnt != 1)
-       ereport(ERROR,
-               (errcode(ERRCODE_OBJECT_IN_USE),
-                errmsg("cannot drop \"%s\" because "
-                       "it is being used by active queries in this session",
-                       RelationGetRelationName(rel))));
+   CheckTableNotInUse(rel, "DROP TABLE");
 
    /*
     * Schedule unlinking of the relation's physical files at commit.

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index f4087fedd04206d8ecc0f0c96e536278e6cbf455..73b5e6b91c4ab03c2f40eadee03648c133b3622d 100644 (file)
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -910,6 +910,12 @@ index_drop(Oid indexId)
 
    userIndexRelation = index_open(indexId, AccessExclusiveLock);
 
+   /*
+    * There can no longer be anyone *else* touching the index, but we
+    * might still have open queries using it in our own session.
+    */
+   CheckTableNotInUse(userIndexRelation, "DROP INDEX");
+
    /*
     * Schedule physical removal of the files
     */

diff --git a/src/interfaces/ecpg/test/expected/sql-fetch.stderr b/src/interfaces/ecpg/test/expected/sql-fetch.stderr
index 4a9d331464d1af1bba19554f8d2a2a215595d692..8eae2b205209d8b494c252e8278640dd7c1f7fae 100644 (file)
--- a/src/interfaces/ecpg/test/expected/sql-fetch.stderr
+++ b/src/interfaces/ecpg/test/expected/sql-fetch.stderr
@@ -138,10 +138,10 @@
 [NO_PID]: sqlca: code: 0, state: 00000
 [NO_PID]: ecpg_execute on line 53: using PQexec
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: ecpg_check_PQresult on line 53: ERROR:  cannot drop "my_table" because it is being used by active queries in this session
+[NO_PID]: ecpg_check_PQresult on line 53: ERROR:  cannot DROP TABLE "my_table" because it is being used by active queries in this session
 [NO_PID]: sqlca: code: 0, state: 00000
-[NO_PID]: raising sqlstate 55006 (sqlcode -400) on line 53: cannot drop "my_table" because it is being used by active queries in this session on line 53
+[NO_PID]: raising sqlstate 55006 (sqlcode -400) on line 53: cannot DROP TABLE "my_table" because it is being used by active queries in this session on line 53
 [NO_PID]: sqlca: code: -400, state: 55006
-SQL error: cannot drop "my_table" because it is being used by active queries in this session on line 53
+SQL error: cannot DROP TABLE "my_table" because it is being used by active queries in this session on line 53
 [NO_PID]: ecpg_finish: connection regress1 closed
 [NO_PID]: sqlca: code: 0, state: 00000