\t on
EXPLAIN (VERBOSE, COSTS FALSE) SELECT * FROM agg_text WHERE a > 0;
\t off
+-- file FDW allows foreign tables to be accessed without user mapping
+DROP USER MAPPING FOR file_fdw_user SERVER file_server;
+SELECT * FROM agg_text ORDER BY a;
-- privilege tests for object
SET ROLE file_fdw_superuser;
Foreign File: @abs_srcdir@/data/agg.data
\t off
+-- file FDW allows foreign tables to be accessed without user mapping
+DROP USER MAPPING FOR file_fdw_user SERVER file_server;
+SELECT * FROM agg_text ORDER BY a;
+ a | b
+-----+---------
+ 0 | 0.09561
+ 42 | 324.78
+ 56 | 7.8
+ 100 | 99.097
+(4 rows)
+
-- privilege tests for object
SET ROLE file_fdw_superuser;
ALTER FOREIGN TABLE agg_text OWNER TO file_fdw_user;
-- cleanup
RESET ROLE;
DROP EXTENSION file_fdw CASCADE;
-NOTICE: drop cascades to 8 other objects
+NOTICE: drop cascades to 7 other objects
DETAIL: drop cascades to server file_server
-drop cascades to user mapping for file_fdw_user on server file_server
drop cascades to user mapping for file_fdw_superuser on server file_server
drop cascades to user mapping for no_priv_user on server file_server
drop cascades to foreign table agg_text
-- change the session user to view_owner and execute the statement. Because of
-- change in session user, the plan should get invalidated and created again.
--- While creating the plan, it should throw error since there is no user mapping
--- available for view_owner.
+-- The join will not be pushed down since the joining relations do not have a
+-- valid user mapping.
SET SESSION ROLE view_owner;
EXPLAIN (COSTS OFF, VERBOSE) EXECUTE join_stmt;
-ERROR: user mapping not found for "view_owner"
-EXECUTE join_stmt;
-ERROR: user mapping not found for "view_owner"
+ QUERY PLAN
+------------------------------------------------------------------
+ Limit
+ Output: t1.c1, t2.c1
+ -> Sort
+ Output: t1.c1, t2.c1
+ Sort Key: t1.c1, t2.c1
+ -> Hash Left Join
+ Output: t1.c1, t2.c1
+ Hash Cond: (t1.c1 = t2.c1)
+ -> Foreign Scan on public.ft4 t1
+ Output: t1.c1, t1.c2, t1.c3
+ Remote SQL: SELECT c1 FROM "S 1"."T 3"
+ -> Hash
+ Output: t2.c1
+ -> Foreign Scan on public.ft5 t2
+ Output: t2.c1
+ Remote SQL: SELECT c1 FROM "S 1"."T 4"
+(16 rows)
+
RESET ROLE;
DEALLOCATE join_stmt;
CREATE VIEW v_ft5 AS SELECT * FROM ft5;
----+----
(0 rows)
+-- If a sub-join can't be pushed down, upper level join shouldn't be either.
+EXPLAIN (COSTS false, VERBOSE)
+SELECT t1.c1, t2.c1 FROM (ft5 t1 JOIN v_ft5 t2 ON (t1.c1 = t2.c1)) left join (ft5 t3 JOIN v_ft5 t4 ON (t3.c1 = t4.c1)) ON (t1.c1 = t3.c1);
+ QUERY PLAN
+------------------------------------------------------------------
+ Hash Join
+ Output: t1.c1, ft5.c1
+ Hash Cond: (t1.c1 = ft5.c1)
+ -> Hash Right Join
+ Output: t1.c1
+ Hash Cond: (t3.c1 = t1.c1)
+ -> Hash Join
+ Output: t3.c1
+ Hash Cond: (t3.c1 = ft5_1.c1)
+ -> Foreign Scan on public.ft5 t3
+ Output: t3.c1, t3.c2, t3.c3
+ Remote SQL: SELECT c1 FROM "S 1"."T 4"
+ -> Hash
+ Output: ft5_1.c1
+ -> Foreign Scan on public.ft5 ft5_1
+ Output: ft5_1.c1
+ Remote SQL: SELECT c1 FROM "S 1"."T 4"
+ -> Hash
+ Output: t1.c1
+ -> Foreign Scan on public.ft5 t1
+ Output: t1.c1
+ Remote SQL: SELECT c1 FROM "S 1"."T 4"
+ -> Hash
+ Output: ft5.c1
+ -> Foreign Scan on public.ft5
+ Output: ft5.c1
+ Remote SQL: SELECT c1 FROM "S 1"."T 4"
+(27 rows)
+
-- recreate the dropped user mapping for further tests
CREATE USER MAPPING FOR CURRENT_USER SERVER loopback;
DROP USER MAPPING FOR PUBLIC SERVER loopback;
List *joinclauses;
List *otherclauses;
+ /*
+ * Core code may call GetForeignJoinPaths hook even when the join
+ * relation doesn't have a valid user mapping associated with it. See
+ * build_join_rel() for details. We can't push down such join, since
+ * there doesn't exist a user mapping which can be used to connect to the
+ * foreign server.
+ */
+ if (!OidIsValid(joinrel->umid))
+ return false;
+
/*
* We support pushing down INNER, LEFT, RIGHT and FULL OUTER joins.
* Constructing queries representing SEMI and ANTI joins is hard, hence
EXECUTE join_stmt;
-- change the session user to view_owner and execute the statement. Because of
-- change in session user, the plan should get invalidated and created again.
--- While creating the plan, it should throw error since there is no user mapping
--- available for view_owner.
+-- The join will not be pushed down since the joining relations do not have a
+-- valid user mapping.
SET SESSION ROLE view_owner;
EXPLAIN (COSTS OFF, VERBOSE) EXECUTE join_stmt;
-EXECUTE join_stmt;
RESET ROLE;
DEALLOCATE join_stmt;
EXPLAIN (COSTS false, VERBOSE) EXECUTE join_stmt;
EXECUTE join_stmt;
+-- If a sub-join can't be pushed down, upper level join shouldn't be either.
+EXPLAIN (COSTS false, VERBOSE)
+SELECT t1.c1, t2.c1 FROM (ft5 t1 JOIN v_ft5 t2 ON (t1.c1 = t2.c1)) left join (ft5 t3 JOIN v_ft5 t4 ON (t3.c1 = t4.c1)) ON (t1.c1 = t3.c1);
+
-- recreate the dropped user mapping for further tests
CREATE USER MAPPING FOR CURRENT_USER SERVER loopback;
DROP USER MAPPING FOR PUBLIC SERVER loopback;
extern Datum pg_options_to_table(PG_FUNCTION_ARGS);
extern Datum postgresql_fdw_validator(PG_FUNCTION_ARGS);
-static HeapTuple find_user_mapping(Oid userid, Oid serverid);
+static HeapTuple find_user_mapping(Oid userid, Oid serverid, bool missing_ok);
/*
* GetForeignDataWrapper - look up the foreign-data wrapper by OID.
bool isnull;
UserMapping *um;
- tp = find_user_mapping(userid, serverid);
+ tp = find_user_mapping(userid, serverid, false);
um = (UserMapping *) palloc(sizeof(UserMapping));
um->umid = HeapTupleGetOid(tp);
*
* If no mapping is found for the supplied user, we also look for
* PUBLIC mappings (userid == InvalidOid).
+ *
+ * If missing_ok is true, the function returns InvalidOid when it does not find
+ * required user mapping. Otherwise, find_user_mapping() throws error if it
+ * does not find required user mapping.
*/
Oid
-GetUserMappingId(Oid userid, Oid serverid)
+GetUserMappingId(Oid userid, Oid serverid, bool missing_ok)
{
HeapTuple tp;
Oid umid;
- tp = find_user_mapping(userid, serverid);
+ tp = find_user_mapping(userid, serverid, missing_ok);
+
+ Assert(missing_ok || tp);
+
+ if (!tp && missing_ok)
+ return InvalidOid;
/* Extract the Oid */
umid = HeapTupleGetOid(tp);
*
* If no mapping is found for the supplied user, we also look for
* PUBLIC mappings (userid == InvalidOid).
+ *
+ * If missing_ok is true, the function returns NULL, if it does not find
+ * the required user mapping. Otherwise, it throws error if it does not
+ * find the required user mapping.
*/
static HeapTuple
-find_user_mapping(Oid userid, Oid serverid)
+find_user_mapping(Oid userid, Oid serverid, bool missing_ok)
{
HeapTuple tp;
ObjectIdGetDatum(serverid));
if (!HeapTupleIsValid(tp))
- ereport(ERROR,
- (errcode(ERRCODE_UNDEFINED_OBJECT),
- errmsg("user mapping not found for \"%s\"",
- MappingUserName(userid))));
+ {
+ if (missing_ok)
+ return NULL;
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_OBJECT),
+ errmsg("user mapping not found for \"%s\"",
+ MappingUserName(userid))));
+ }
return tp;
}
* ensure that it gets invalidated in the case of a user OID change.
* See RevalidateCachedQuery and more generally the hasForeignJoin
* flags in PlannerGlobal and PlannedStmt.
+ *
+ * It's possible, and not necessarily an error, for rel->umid to be
+ * InvalidOid even though rel->serverid is set. That just means there
+ * is a server with no user mapping.
*/
Oid userid;
userid = OidIsValid(rte->checkAsUser) ? rte->checkAsUser : GetUserId();
- rel->umid = GetUserMappingId(userid, rel->serverid);
+ rel->umid = GetUserMappingId(userid, rel->serverid, true);
}
else
rel->umid = InvalidOid;
*
* Otherwise those fields are left invalid, so FDW API will not be called
* for the join relation.
+ *
+ * For FDWs like file_fdw, which ignore user mapping, the user mapping id
+ * associated with the joining relation may be invalid. A valid serverid
+ * distinguishes between a pushed down join with no user mapping and
+ * a join which can not be pushed down because of user mapping mismatch.
*/
if (OidIsValid(outer_rel->serverid) &&
inner_rel->serverid == outer_rel->serverid &&
inner_rel->umid == outer_rel->umid)
{
- Assert(OidIsValid(outer_rel->umid));
joinrel->serverid = outer_rel->serverid;
joinrel->umid = outer_rel->umid;
joinrel->fdwroutine = outer_rel->fdwroutine;
extern ForeignServer *GetForeignServer(Oid serverid);
extern ForeignServer *GetForeignServerByName(const char *name, bool missing_ok);
extern UserMapping *GetUserMapping(Oid userid, Oid serverid);
-extern Oid GetUserMappingId(Oid userid, Oid serverid);
+extern Oid GetUserMappingId(Oid userid, Oid serverid, bool missing_ok);
extern UserMapping *GetUserMappingById(Oid umid);
extern ForeignDataWrapper *GetForeignDataWrapper(Oid fdwid);
extern ForeignDataWrapper *GetForeignDataWrapperByName(const char *name,
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