Foreign Key: Add support for multi target delete

go/test/endtoend/vtgate/foreignkey/fk_fuzz_test.go

@@ -214,7 +214,11 @@ func (fz *fuzzer) generateMultiDeleteDMLQuery() string {
 	tableId2 := rand.Intn(len(fkTables))
 	idValue := 1 + rand.Intn(fz.maxValForId)
 	setVarFkChecksVal := fz.getSetVarFkChecksVal()
-	query := fmt.Sprintf("delete %v%v from %v join %v using (id) where %v.id = %v", setVarFkChecksVal, fkTables[tableId], fkTables[tableId], fkTables[tableId2], fkTables[tableId], idValue)
+	target := fkTables[tableId]
+	if rand.Intn(2)%2 == 0 {
+		target += ", " + fkTables[tableId2]
+	}
+	query := fmt.Sprintf("delete %v%v from %v join %v using (id) where %v.id = %v", setVarFkChecksVal, target, fkTables[tableId], fkTables[tableId2], fkTables[tableId], idValue)
 	return query
 }
 

go/test/endtoend/vtgate/foreignkey/fk_test.go

@@ -704,6 +704,22 @@ func TestFkScenarios(t *testing.T) {
 				"select * from fk_multicol_t17 order by id",
 				"select * from fk_multicol_t19 order by id",
 			},
+		}, {
+			name: "Multi Target Delete success",
+			dataQueries: []string{
+				"insert into fk_multicol_t15(id, cola, colb) values (1, 7, 1), (2, 9, 1), (3, 11, 1), (4, 13, 1)",
+				"insert into fk_multicol_t16(id, cola, colb) values (1, 7, 1), (2, 9, 1), (3, 11, 1), (4, 13, 1)",
+				"insert into fk_multicol_t17(id, cola, colb) values (1, 7, 1), (2, 9, 1), (3, 11, 1)",
+				"insert into fk_multicol_t18(id, cola, colb) values (1, 7, 1), (3, 11, 1)",
+				"insert into fk_multicol_t19(id, cola, colb) values (1, 7, 1), (2, 9, 1)",
+			},
+			dmlQuery: "delete fk_multicol_t15, fk_multicol_t17 from fk_multicol_t15 join fk_multicol_t17 where fk_multicol_t15.id = fk_multicol_t17.id",
+			assertionQueries: []string{
+				"select * from fk_multicol_t15 order by id",
+				"select * from fk_multicol_t16 order by id",
+				"select * from fk_multicol_t17 order by id",
+				"select * from fk_multicol_t19 order by id",
+			},
 		}, {
 			name: "Delete with limit success",
 			dataQueries: []string{

go/vt/vtgate/planbuilder/operators/delete.go

@@ -84,6 +84,11 @@ func createOperatorFromDelete(ctx *plancontext.PlanningContext, deleteStmt *sqlp
 		}
 	}
 
+	var err error
+	childFks, err = ctx.SemTable.GetChildForeignKeysForTable(deleteStmt.Targets[0])
+	if err != nil {
+		panic(err)
+	}
 	// If there are no foreign key constraints, then we don't need to do anything special.
 	if len(childFks) == 0 {
 		return op
@@ -94,9 +99,6 @@ func createOperatorFromDelete(ctx *plancontext.PlanningContext, deleteStmt *sqlp
 
 func deleteWithInputPlanningRequired(childFks []vindexes.ChildFKInfo, deleteStmt *sqlparser.Delete) bool {
 	if len(deleteStmt.Targets) > 1 {
-		if len(childFks) > 0 {
-			panic(vterrors.VT12001("multi table delete with foreign keys"))
-		}
 		return true
 	}
 	// If there are no foreign keys, we don't need to use delete with input.
@@ -354,6 +356,7 @@ func updateQueryGraphWithSource(ctx *plancontext.PlanningContext, input Operator
 func createFkCascadeOpForDelete(ctx *plancontext.PlanningContext, parentOp Operator, delStmt *sqlparser.Delete, childFks []vindexes.ChildFKInfo, deletedTbl *vindexes.Table) Operator {
 	var fkChildren []*FkChild
 	var selectExprs []sqlparser.SelectExpr
+	tblName := delStmt.Targets[0]
 	for _, fk := range childFks {
 		// Any RESTRICT type foreign keys that arrive here,
 		// are cross-shard/cross-keyspace RESTRICT cases, which we don't currently support.
@@ -363,7 +366,7 @@ func createFkCascadeOpForDelete(ctx *plancontext.PlanningContext, parentOp Opera
 
 		// We need to select all the parent columns for the foreign key constraint, to use in the update of the child table.
 		var offsets []int
-		offsets, selectExprs = addColumns(ctx, fk.ParentColumns, selectExprs, deletedTbl.GetTableName())
+		offsets, selectExprs = addColumns(ctx, fk.ParentColumns, selectExprs, tblName)
 
 		fkChildren = append(fkChildren,
 			createFkChildForDelete(ctx, fk, offsets))

go/vt/vtgate/planbuilder/testdata/foreignkey_cases.json

@@ -3151,8 +3151,8 @@
                   "Name": "unsharded_fk_allow",
                   "Sharded": false
                 },
-                "FieldQuery": "select u_tbl6.col6 from u_tbl6 as u where 1 != 1",
-                "Query": "select u_tbl6.col6 from u_tbl6 as u where u.id in ::dml_vals for update",
+                "FieldQuery": "select u.col6 from u_tbl6 as u where 1 != 1",
+                "Query": "select u.col6 from u_tbl6 as u where u.id in ::dml_vals for update",
                 "Table": "u_tbl6"
               },
               {
@@ -3805,7 +3805,92 @@
   {
     "comment": "multi table delete on foreign key enabled tables",
     "query": "delete u, m from u_tbl6 u join u_tbl5 m on u.col = m.col where u.col2 = 4 and m.col3 = 6",
-    "plan": "VT12001: unsupported: multi table delete with foreign keys"
+    "plan": {
+      "QueryType": "DELETE",
+      "Original": "delete u, m from u_tbl6 u join u_tbl5 m on u.col = m.col where u.col2 = 4 and m.col3 = 6",
+      "Instructions": {
+        "OperatorType": "DMLWithInput",
+        "TargetTabletType": "PRIMARY",
+        "Offset": [
+          "0:[0]",
+          "1:[1]"
+        ],
+        "Inputs": [
+          {
+            "OperatorType": "Route",
+            "Variant": "Unsharded",
+            "Keyspace": {
+              "Name": "unsharded_fk_allow",
+              "Sharded": false
+            },
+            "FieldQuery": "select u.id, m.id from u_tbl6 as u, u_tbl5 as m where 1 != 1",
+            "Query": "select u.id, m.id from u_tbl6 as u, u_tbl5 as m where u.col2 = 4 and m.col3 = 6 and u.col = m.col for update",
+            "Table": "u_tbl5, u_tbl6"
+          },
+          {
+            "OperatorType": "FkCascade",
+            "Inputs": [
+              {
+                "InputName": "Selection",
+                "OperatorType": "Route",
+                "Variant": "Unsharded",
+                "Keyspace": {
+                  "Name": "unsharded_fk_allow",
+                  "Sharded": false
+                },
+                "FieldQuery": "select u.col6 from u_tbl6 as u where 1 != 1",
+                "Query": "select u.col6 from u_tbl6 as u where u.id in ::dml_vals for update",
+                "Table": "u_tbl6"
+              },
+              {
+                "InputName": "CascadeChild-1",
+                "OperatorType": "Delete",
+                "Variant": "Unsharded",
+                "Keyspace": {
+                  "Name": "unsharded_fk_allow",
+                  "Sharded": false
+                },
+                "TargetTabletType": "PRIMARY",
+                "BvName": "fkc_vals",
+                "Cols": [
+                  0
+                ],
+                "Query": "delete from u_tbl8 where (col8) in ::fkc_vals",
+                "Table": "u_tbl8"
+              },
+              {
+                "InputName": "Parent",
+                "OperatorType": "Delete",
+                "Variant": "Unsharded",
+                "Keyspace": {
+                  "Name": "unsharded_fk_allow",
+                  "Sharded": false
+                },
+                "TargetTabletType": "PRIMARY",
+                "Query": "delete from u_tbl6 as u where u.id in ::dml_vals",
+                "Table": "u_tbl6"
+              }
+            ]
+          },
+          {
+            "OperatorType": "Delete",
+            "Variant": "Unsharded",
+            "Keyspace": {
+              "Name": "unsharded_fk_allow",
+              "Sharded": false
+            },
+            "TargetTabletType": "PRIMARY",
+            "Query": "delete from u_tbl5 as m where m.id in ::dml_vals",
+            "Table": "u_tbl5"
+          }
+        ]
+      },
+      "TablesUsed": [
+        "unsharded_fk_allow.u_tbl5",
+        "unsharded_fk_allow.u_tbl6",
+        "unsharded_fk_allow.u_tbl8"
+      ]
+    }
   },
   {
     "comment": "update with limit with foreign keys",

go/vt/vtgate/semantics/semantic_state.go

@@ -198,9 +198,13 @@ func (st *SemTable) GetChildForeignKeysForTargets() (fks []vindexes.ChildFKInfo)
 	return fks
 }
 
-// GetChildForeignKeysForTableSet gets the child foreign keys as a list for the specified TableSet.
-func (st *SemTable) GetChildForeignKeysForTableSet(ts TableSet) []vindexes.ChildFKInfo {
-	return st.childForeignKeysInvolved[ts]
+// GetChildForeignKeysForTable gets the child foreign keys as a list for the specified TableName.
+func (st *SemTable) GetChildForeignKeysForTable(tbl sqlparser.TableName) ([]vindexes.ChildFKInfo, error) {
+	ts, err := st.GetTargetTableSetForTableName(tbl)
+	if err != nil {
+		return nil, err
+	}
+	return st.childForeignKeysInvolved[ts], nil
 }
 
 // GetChildForeignKeysList gets the child foreign keys as a list.