Allow SET TABLESPACE to database default

We've always allowed CREATE TABLE to create tables in the database's default
tablespace without checking for CREATE permissions on that tablespace.
Unfortunately, the original implementation of ALTER TABLE ... SET TABLESPACE
didn't pick up on that exception.

This changes ALTER TABLE ... SET TABLESPACE to allow the database's default
tablespace without checking for CREATE rights on that tablespace, just as
CREATE TABLE works today.  Users could always do this through a series of
commands (CREATE TABLE ... AS SELECT * FROM ...; DROP TABLE ...; etc), so
let's fix the oversight in SET TABLESPACE's original implementation.

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 5d64461cdaa960c9a2caa6524dbe1176bddde61d..7c1f779d721eca148d01877e16b9e086ca739f1c 100644 (file)
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8462,21 +8462,26 @@ static void
 ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, char *tablespacename, LOCKMODE lockmode)
 {
        Oid                     tablespaceId;
-       AclResult       aclresult;
 
        /* Check that the tablespace exists */
        tablespaceId = get_tablespace_oid(tablespacename, false);
 
-       /* Check its permissions */
-       aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE);
-       if (aclresult != ACLCHECK_OK)
-               aclcheck_error(aclresult, ACL_KIND_TABLESPACE, tablespacename);
+       /* Check permissions except when moving to database's default */
+       if (OidIsValid(tablespaceId) && tablespaceId != MyDatabaseTableSpace)
+       {
+               AclResult       aclresult;
+
+               aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE);
+               if (aclresult != ACLCHECK_OK)
+                       aclcheck_error(aclresult, ACL_KIND_TABLESPACE, tablespacename);
+       }
 
        /* Save info for Phase 3 to do the real work */
        if (OidIsValid(tab->newTableSpace))
                ereport(ERROR,
                                (errcode(ERRCODE_SYNTAX_ERROR),
                                 errmsg("cannot have multiple SET TABLESPACE subcommands")));
+
        tab->newTableSpace = tablespaceId;
 }