From 33e948941c8a19493fbdfc879ce29ea3d1e97834 Mon Sep 17 00:00:00 2001
From: xhe <xw897002528@gmail.com>
Date: Sat, 1 Jan 2022 15:53:51 +0800
Subject: [PATCH] placement: remove isolation level and constraints completely
 (#31189)

close pingcap/tidb#31052
---
 ddl/placement/bundle_test.go |  2 +-
 ddl/placement/rule.go        | 30 +++++++++++++-----------------
 2 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/ddl/placement/bundle_test.go b/ddl/placement/bundle_test.go
index 9309db9d17..94c51795f2 100644
--- a/ddl/placement/bundle_test.go
+++ b/ddl/placement/bundle_test.go
@@ -352,7 +352,7 @@ func (s *testBundleSuite) TestString(c *C) {
 	c.Assert(err, IsNil)
 	bundle.Rules = append(rules1, rules2...)
 
-	c.Assert(bundle.String(), Equals, `{"group_id":"TiDB_DDL_1","group_index":0,"group_override":false,"rules":[{"group_id":"","id":"","start_key":"","end_key":"","role":"voter","count":3,"label_constraints":[{"key":"zone","op":"in","values":["sh"]}],"location_labels":["region","zone","rack","host"]},{"group_id":"","id":"","start_key":"","end_key":"","role":"voter","count":4,"label_constraints":[{"key":"zone","op":"notIn","values":["sh"]},{"key":"zone","op":"in","values":["bj"]}],"location_labels":["region","zone","rack","host"]}]}`)
+	c.Assert(bundle.String(), Equals, "{\"group_id\":\"TiDB_DDL_1\",\"group_index\":0,\"group_override\":false,\"rules\":[{\"group_id\":\"\",\"id\":\"\",\"start_key\":\"\",\"end_key\":\"\",\"role\":\"voter\",\"count\":3,\"label_constraints\":[{\"key\":\"zone\",\"op\":\"in\",\"values\":[\"sh\"]}]},{\"group_id\":\"\",\"id\":\"\",\"start_key\":\"\",\"end_key\":\"\",\"role\":\"voter\",\"count\":4,\"label_constraints\":[{\"key\":\"zone\",\"op\":\"notIn\",\"values\":[\"sh\"]},{\"key\":\"zone\",\"op\":\"in\",\"values\":[\"bj\"]}]}]}")
 
 	c.Assert(failpoint.Enable("github.com/pingcap/tidb/ddl/placement/MockMarshalFailure", `return(true)`), IsNil)
 	defer func() {
diff --git a/ddl/placement/rule.go b/ddl/placement/rule.go
index 74a3130167..c8528ef2df 100644
--- a/ddl/placement/rule.go
+++ b/ddl/placement/rule.go
@@ -38,27 +38,24 @@ const (
 
 // Rule is the core placement rule struct. Check https://github.com/tikv/pd/blob/master/server/schedule/placement/rule.go.
 type Rule struct {
-	GroupID        string       `json:"group_id"`
-	ID             string       `json:"id"`
-	Index          int          `json:"index,omitempty"`
-	Override       bool         `json:"override,omitempty"`
-	StartKeyHex    string       `json:"start_key"`
-	EndKeyHex      string       `json:"end_key"`
-	Role           PeerRoleType `json:"role"`
-	Count          int          `json:"count"`
-	Constraints    Constraints  `json:"label_constraints,omitempty"`
-	LocationLabels []string     `json:"location_labels,omitempty"`
-	IsolationLevel string       `json:"isolation_level,omitempty"`
+	GroupID     string       `json:"group_id"`
+	ID          string       `json:"id"`
+	Index       int          `json:"index,omitempty"`
+	Override    bool         `json:"override,omitempty"`
+	StartKeyHex string       `json:"start_key"`
+	EndKeyHex   string       `json:"end_key"`
+	Role        PeerRoleType `json:"role"`
+	Count       int          `json:"count"`
+	Constraints Constraints  `json:"label_constraints,omitempty"`
 }
 
 // NewRule constructs *Rule from role, count, and constraints. It is here to
 // consistent the behavior of creating new rules.
 func NewRule(role PeerRoleType, replicas uint64, cnst Constraints) *Rule {
 	return &Rule{
-		Role:           role,
-		Count:          int(replicas),
-		Constraints:    cnst,
-		LocationLabels: []string{"region", "zone", "rack", "host"},
+		Role:        role,
+		Count:       int(replicas),
+		Constraints: cnst,
 	}
 }
 
@@ -119,8 +116,7 @@ func NewRules(role PeerRoleType, replicas uint64, cnstr string) ([]*Rule, error)
 }
 
 // Clone is used to duplicate a RuleOp for safe modification.
-// Note that it is a shallow copy: LocationLabels and Constraints
-// is not cloned.
+// Note that it is a shallow copy: Constraints is not cloned.
 func (r *Rule) Clone() *Rule {
 	n := &Rule{}
 	*n = *r