Fix Assert failure for MERGE into a partitioned table with RLS.

In ExecInitPartitionInfo(), the Assert when building the WITH CHECK
OPTION list for the new partition assumed that the command would be an
INSERT or UPDATE, but it can also be a MERGE. This can be triggered by
a MERGE into a partitioned table with RLS checks to enforce.

Fix, and back-patch to v15, where MERGE was introduced.

Discussion: https://postgr.es/m/CAEZATCWWFtQmW67F3XTyMU5Am10Oxa_b8oe0x%2BNu5Mo%2BCdRErg%40mail.gmail.com

diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index 651ad24fc10ac48c3814fe9d98bcd48e87b440fb..fd6ca8a5d9a312e2933a599d7a177209bbef85d1 100644 (file)
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -545,8 +545,8 @@ ExecInitPartitionInfo(ModifyTableState *mtstate, EState *estate,
         * Build WITH CHECK OPTION constraints for the partition.  Note that we
         * didn't build the withCheckOptionList for partitions within the planner,
         * but simple translation of varattnos will suffice.  This only occurs for
-        * the INSERT case or in the case of UPDATE tuple routing where we didn't
-        * find a result rel to reuse.
+        * the INSERT case or in the case of UPDATE/MERGE tuple routing where we
+        * didn't find a result rel to reuse.
         */
        if (node && node->withCheckOptionLists != NIL)
        {
@@ -557,12 +557,15 @@ ExecInitPartitionInfo(ModifyTableState *mtstate, EState *estate,
                /*
                 * In the case of INSERT on a partitioned table, there is only one
                 * plan.  Likewise, there is only one WCO list, not one per partition.
-                * For UPDATE, there are as many WCO lists as there are plans.
+                * For UPDATE/MERGE, there are as many WCO lists as there are plans.
                 */
                Assert((node->operation == CMD_INSERT &&
                                list_length(node->withCheckOptionLists) == 1 &&
                                list_length(node->resultRelations) == 1) ||
                           (node->operation == CMD_UPDATE &&
+                               list_length(node->withCheckOptionLists) ==
+                               list_length(node->resultRelations)) ||
+                          (node->operation == CMD_MERGE &&
                                list_length(node->withCheckOptionLists) ==
                                list_length(node->resultRelations)));
 
@@ -619,6 +622,7 @@ ExecInitPartitionInfo(ModifyTableState *mtstate, EState *estate,
                List       *returningList;
 
                /* See the comment above for WCO lists. */
+               /* (except no RETURNING support for MERGE yet) */
                Assert((node->operation == CMD_INSERT &&
                                list_length(node->returningLists) == 1 &&
                                list_length(node->resultRelations) == 1) ||

diff --git a/src/test/regress/expected/merge.out b/src/test/regress/expected/merge.out
index c298bfa314cf135bd1280994d1e212ed685e437d..e1d363966c798e62d6e0c18106009b631136473a 100644 (file)
--- a/src/test/regress/expected/merge.out
+++ b/src/test/regress/expected/merge.out
@@ -1736,6 +1736,18 @@ SELECT * FROM pa_target ORDER BY tid;
   14 |     140 | inserted by merge
 (14 rows)
 
+ROLLBACK;
+-- test RLS enforcement
+BEGIN;
+ALTER TABLE pa_target ENABLE ROW LEVEL SECURITY;
+ALTER TABLE pa_target FORCE ROW LEVEL SECURITY;
+CREATE POLICY pa_target_pol ON pa_target USING (tid != 0);
+MERGE INTO pa_target t
+  USING pa_source s
+  ON t.tid = s.sid AND t.tid IN (1,2,3,4)
+  WHEN MATCHED THEN
+    UPDATE SET tid = tid - 1;
+ERROR:  new row violates row-level security policy for table "pa_target"
 ROLLBACK;
 DROP TABLE pa_source;
 DROP TABLE pa_target CASCADE;

diff --git a/src/test/regress/sql/merge.sql b/src/test/regress/sql/merge.sql
index 9ed648ad1f6e06b3650cff1dafca67a7be30de27..f0854162a792c9bf28b1ced0b35670fde3ec07fe 100644 (file)
--- a/src/test/regress/sql/merge.sql
+++ b/src/test/regress/sql/merge.sql
@@ -1082,6 +1082,18 @@ MERGE INTO pa_target t
 SELECT * FROM pa_target ORDER BY tid;
 ROLLBACK;
 
+-- test RLS enforcement
+BEGIN;
+ALTER TABLE pa_target ENABLE ROW LEVEL SECURITY;
+ALTER TABLE pa_target FORCE ROW LEVEL SECURITY;
+CREATE POLICY pa_target_pol ON pa_target USING (tid != 0);
+MERGE INTO pa_target t
+  USING pa_source s
+  ON t.tid = s.sid AND t.tid IN (1,2,3,4)
+  WHEN MATCHED THEN
+    UPDATE SET tid = tid - 1;
+ROLLBACK;
+
 DROP TABLE pa_source;
 DROP TABLE pa_target CASCADE;