plan: use point get plan for UPDATE statement

cmd/explaintest/r/explain_easy.result

@@ -50,8 +50,7 @@ IndexJoin_11 4166.67 root left outer join, inner:IndexLookUp_10, outer key:test.
  └─TableScan_9 10.00 cop table:t2, keep order:false, stats:pseudo
 explain update t1 set t1.c2 = 2 where t1.c1 = 1;
 id count task operator info
-TableReader_5 1.00 root data:TableScan_4
-└─TableScan_4 1.00 cop table:t1, range:[1,1], keep order:false, stats:pseudo
+Point_Get_1 1.00 root table:t1, handle:1
 explain delete from t1 where t1.c2 = 1;
 id count task operator info
 IndexLookUp_9 10.00 root 

cmd/explaintest/r/explain_easy_stats.result

@@ -56,8 +56,7 @@ Projection_6 2481.25 root test.t1.c1, test.t1.c2, test.t1.c3, test.t2.c1, test.t
  └─TableScan_20 1985.00 cop table:t2, keep order:false
 explain update t1 set t1.c2 = 2 where t1.c1 = 1;
 id count task operator info
-TableReader_5 1.00 root data:TableScan_4
-└─TableScan_4 1.00 cop table:t1, range:[1,1], keep order:false
+Point_Get_1 1.00 root table:t1, handle:1
 explain delete from t1 where t1.c2 = 1;
 id count task operator info
 IndexLookUp_9 0.00 root 

domain/schema_validator_test.go

@@ -95,6 +95,7 @@ func (*testSuite) TestSchemaValidator(c *C) {
  c.Assert(valid, Equals, ResultUnknown)
 
  close(exit)
+ time.Sleep(time.Millisecond)
 }
 
 func reload(validator SchemaValidator, leaseGrantCh chan leaseGrantItem, ids ...int64) int64 {

expression/simple_rewriter.go

@@ -137,6 +137,11 @@ func (sr *simpleRewriter) Leave(originInNode ast.Node) (retNode ast.Node, ok boo
  if v.Sel == nil {
  sr.inToExpression(len(v.List), v.Not, &v.Type)
  }
+ case *ast.ParamMarkerExpr:
+ tp := types.NewFieldType(mysql.TypeUnspecified)
+ types.DefaultParamTypeForValue(v.GetValue(), tp)
+ value := &Constant{Value: v.Datum, RetType: tp}
+ sr.push(value)
  case *ast.RowExpr:
  sr.rowToScalarFunc(v)
  case *ast.ParenthesesExpr:

plan/point_get_plan.go

@@ -127,6 +127,8 @@ func tryFastPlan(ctx sessionctx.Context, node ast.Node) Plan {
  }
  return fp
  }
+ case *ast.UpdateStmt:
+ return tryUpdatePointPlan(ctx, x)
  case *ast.DeleteStmt:
  return tryDeletePointPlan(ctx, x)
  }
@@ -382,6 +384,57 @@ func findInPairs(colName string, pairs []nameValuePair) int {
  return -1
 }
 
+func tryUpdatePointPlan(ctx sessionctx.Context, updateStmt *ast.UpdateStmt) Plan {
+ selStmt := &ast.SelectStmt{
+ Fields: &ast.FieldList{},
+ From: updateStmt.TableRefs,
+ Where: updateStmt.Where,
+ OrderBy: updateStmt.Order,
+ Limit: updateStmt.Limit,
+ }
+ fastSelect := tryPointGetPlan(ctx, selStmt)
+ if fastSelect == nil {
+ return nil
+ }
+ if checkFastPlanPrivilege(ctx, fastSelect, mysql.SelectPriv, mysql.UpdatePriv) != nil {
+ return nil
+ }
+ orderedList := buildOrderedList(ctx, fastSelect, updateStmt.List)
+ if orderedList == nil {
+ return nil
+ }
+ updatePlan := &Update{
+ SelectPlan: fastSelect,
+ OrderedList: orderedList,
+ }
+ updatePlan.SetSchema(fastSelect.schema)
+ return updatePlan
+}
+
+func buildOrderedList(ctx sessionctx.Context, fastSelect *PointGetPlan, list []*ast.Assignment) []*expression.Assignment {
+ orderedList := make([]*expression.Assignment, 0, len(list))
+ for _, assign := range list {
+ col, err := fastSelect.schema.FindColumn(assign.Column)
+ if err != nil {
+ return nil
+ }
+ if col == nil {
+ return nil
+ }
+ newAssign := &expression.Assignment{
+ Col: col,
+ }
+ expr, err := expression.RewriteSimpleExprWithSchema(ctx, assign.Expr, fastSelect.schema)
+ if err != nil {
+ return nil
+ }
+ expr = expression.BuildCastFunction(ctx, expr, col.GetType())
+ newAssign.Expr = expr.ResolveIndices(fastSelect.schema)
+ orderedList = append(orderedList, newAssign)
+ }
+ return orderedList
+}
+
 func tryDeletePointPlan(ctx sessionctx.Context, delStmt *ast.DeleteStmt) Plan {
  if delStmt.IsMultiTable {
  return nil