planner,executor: fix point get for update read panic on partition ta…

…ble (pingcap#25537)

executor/partition_table_test.go

@@ -3018,3 +3018,13 @@ PARTITION BY RANGE (a) (
 	s.testData.GetTestCases(c, &input, &output)
 	s.verifyPartitionResult(tk, input, output)
 }
+
+func (s *partitionTableSuite) TestIssue25528(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("set @@tidb_partition_prune_mode = 'static'")
+	tk.MustExec("use test")
+	tk.MustExec("create table issue25528 (id int primary key, balance DECIMAL(10, 2), balance2 DECIMAL(10, 2) GENERATED ALWAYS AS (-balance) VIRTUAL, created_at TIMESTAMP) PARTITION BY HASH(id) PARTITIONS 8")
+	tk.MustExec("insert into issue25528 (id, balance, created_at) values(1, 100, '2021-06-17 22:35:20')")
+	tk.MustExec("begin pessimistic")
+	tk.MustQuery("select * from issue25528 where id = 1 for update").Check(testkit.Rows("1 100.00 -100.00 2021-06-17 22:35:20"))
+}

planner/core/find_best_task.go

@@ -732,6 +732,15 @@ func (ds *DataSource) findBestTask(prop *property.PhysicalProperty, planCounter
 				if hashPartColName == nil {
 					canConvertPointGet = false
 				}
+			} else {
+				// If the schema contains ExtraPidColID, do not convert to point get.
+				// Because the point get executor can not handle the extra partition ID column now.
+				for _, col := range ds.schema.Columns {
+					if col.ID == model.ExtraPidColID {
+						canConvertPointGet = false
+						break
+					}
+				}
 			}
 		}
 		if canConvertPointGet {