planner: forbid point get with select lock choose tiflash as datasour…

…ce path (#39388)

close #39344

planner/core/find_best_task.go

@@ -912,6 +912,14 @@ func (ds *DataSource) findBestTask(prop *property.PhysicalProperty, planCounter
 				p: dual,
 			}, cntPlan, nil
 		}
+
+		// if the path is the point get range path with for update lock, we should forbid tiflash as it's store path.
+		if path.StoreType == kv.TiFlash && ds.isForUpdateRead && ds.ctx.GetSessionVars().TxnCtx.IsExplicit {
+			if ds.isPointGetConditions() {
+				continue
+			}
+		}
+
 		canConvertPointGet := len(path.Ranges) > 0 && path.StoreType == kv.TiKV && ds.isPointGetConvertableSchema()
 
 		if canConvertPointGet && expression.MaybeOverOptimized4PlanCache(ds.ctx, path.AccessConds) {
@@ -1903,6 +1911,66 @@ func (s *LogicalIndexScan) GetPhysicalIndexScan(_ *expression.Schema, stats *pro
 	return is
 }
 
+// isPointGetConditions indicates whether the conditions are point-get-able.
+// eg: create table t(a int, b int,c int unique, primary (a,b))
+// select * from t where a = 1 and b = 1 and c =1;
+// the datasource can access by primary key(a,b) or unique key (c) which are both point-get-able
+func (ds *DataSource) isPointGetConditions() bool {
+	t, _ := ds.is.TableByID(ds.physicalTableID)
+	columns := map[string]struct{}{}
+	for _, cond := range ds.allConds {
+		s, ok := cond.(*expression.ScalarFunction)
+		if !ok {
+			return false
+		}
+		if s.FuncName.L != ast.EQ || (s.FuncName.L == ast.In && len(s.GetArgs()) != 2) {
+			return false
+		}
+		arg0 := s.GetArgs()[0]
+		arg1 := s.GetArgs()[1]
+		_, ok1 := arg0.(*expression.Constant)
+		col, ok2 := arg1.(*expression.Column)
+		if ok1 && ok2 {
+			columns[t.Meta().FindColumnNameByID(col.ID)] = struct{}{}
+			continue
+		}
+		col, ok1 = arg0.(*expression.Column)
+		_, ok2 = arg1.(*expression.Constant)
+		if ok1 && ok2 {
+			columns[t.Meta().FindColumnNameByID(col.ID)] = struct{}{}
+			continue
+		}
+	}
+	return ds.findPKOrUniqueIndexMatchColumns(columns)
+}
+
+func (ds *DataSource) findPKOrUniqueIndexMatchColumns(columns map[string]struct{}) bool {
+	for _, idx := range ds.tableInfo.Indices {
+		if !idx.Unique && !idx.Primary {
+			continue
+		}
+		if idx.HasPrefixIndex() {
+			continue
+		}
+		if len(idx.Columns) > len(columns) {
+			continue
+		}
+		flag := true
+		for _, idxCol := range idx.Columns {
+			_, ok := columns[idxCol.Name.String()]
+			if !ok {
+				flag = false
+				break
+			}
+		}
+		if !flag {
+			continue
+		}
+		return true
+	}
+	return false
+}
+
 // convertToTableScan converts the DataSource to table scan.
 func (ds *DataSource) convertToTableScan(prop *property.PhysicalProperty, candidate *candidatePath, _ *physicalOptimizeOp) (task task, err error) {
 	// It will be handled in convertToIndexScan.

planner/core/integration_test.go

@@ -7556,6 +7556,40 @@ func TestEnableTiFlashReadForWriteStmt(t *testing.T) {
 	checkMpp(rs)
 }
 
+func TestPointGetWithSelectLock(t *testing.T) {
+	store, dom := testkit.CreateMockStoreAndDomain(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t(a int, b int, primary key(a, b));")
+	tk.MustExec("create table t1(c int unique, d int);")
+	tbl, err := dom.InfoSchema().TableByName(model.CIStr{O: "test", L: "test"}, model.CIStr{O: "t", L: "t"})
+	require.NoError(t, err)
+	// Set the hacked TiFlash replica for explain tests.
+	tbl.Meta().TiFlashReplica = &model.TiFlashReplicaInfo{Count: 1, Available: true}
+	tbl1, err := dom.InfoSchema().TableByName(model.CIStr{O: "test", L: "test"}, model.CIStr{O: "t1", L: "t1"})
+	require.NoError(t, err)
+	// Set the hacked TiFlash replica for explain tests.
+	tbl1.Meta().TiFlashReplica = &model.TiFlashReplicaInfo{Count: 1, Available: true}
+
+	tk.MustExec("set @@tidb_enable_tiflash_read_for_write_stmt = on;")
+	tk.MustExec("set @@tidb_isolation_read_engines='tidb,tiflash';")
+	tk.MustExec("begin;")
+	// assert point get condition with txn commit and tiflash store
+	tk.MustGetErrMsg("explain select a, b from t where a = 1 and b = 2 for update;", "[planner:1815]Internal : Can't find a proper physical plan for this query")
+	tk.MustGetErrMsg("explain select c, d from t1 where c = 1 for update;", "[planner:1815]Internal : Can't find a proper physical plan for this query")
+	tk.MustGetErrMsg("explain select c, d from t1 where c = 1 and d = 1 for update;", "[planner:1815]Internal : Can't find a proper physical plan for this query")
+	tk.MustQuery("explain select a, b from t where a = 1 for update;")
+	tk.MustQuery("explain select c, d from t1 where c > 1 for update;")
+	tk.MustExec("set tidb_isolation_read_engines='tidb,tikv,tiflash';")
+	tk.MustQuery("explain select a, b from t where a = 1 and b = 2 for update;")
+	tk.MustQuery("explain select c, d from t1 where c = 1 for update;")
+	tk.MustExec("commit")
+	tk.MustExec("set tidb_isolation_read_engines='tidb,tiflash';")
+	// assert point get condition with auto commit and tiflash store
+	tk.MustQuery("explain select a, b from t where  a = 1 and b = 2 for update;")
+	tk.MustQuery("explain select c, d from t1 where c = 1 for update;")
+}
+
 func TestTableRangeFallback(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)