Merge branch 'master' into fix

CHANGELOG.md

@@ -1,5 +1,75 @@
 # PD Change Log
 
+## v2.1.2
+- Fix the Region information update issue about Region merge [#1377](https://github.com/pingcap/pd/pull/1377)
+
+## v2.1.1
+- Fix the issue that some configuration items cannot be set to `0` in the configuration file [#1334](https://github.com/pingcap/pd/pull/1334) 
+- Check the undefined configuration when starting PD [#1362](https://github.com/pingcap/pd/pull/1362)
+- Avoid transferring the leader to a newly created peer, to optimize the possible delay [#1339](https://github.com/pingcap/pd/pull/1339)
+- Fix the issue that `RaftCluster` cannot stop caused by deadlock [#1370](https://github.com/pingcap/pd/pull/1370) 
+
+## v2.1.0
++ Optimize availability
+    - Introduce the version control mechanism and support rolling update of the cluster compatibly 
+    - [Enable `Raft PreVote`](https://github.com/pingcap/pd/blob/5c7b18cf3af91098f07cf46df0b59fbf8c7c5462/conf/config.toml#L22) among PD nodes to avoid leader reelection when network recovers after network isolation
+    - Enable `raft learner` by default to lower the risk of unavailable data caused by machine failure during scheduling
+    - TSO allocation is no longer affected by the system clock going backwards
+    - Support the `Region merge` feature to reduce the overhead brought by metadata
+
++ Optimize the scheduler
+    - Optimize the processing of Down Store to speed up making up replicas
+    - Optimize the hotspot scheduler to improve its adaptability when traffic statistics information jitters
+    - Optimize the start of Coordinator to reduce the unnecessary scheduling caused by restarting PD
+    - Optimize the issue that Balance Scheduler schedules small Regions frequently
+    - Optimize Region merge to consider the number of rows within the Region
+    - [Add more commands to control the scheduling policy](https://pingcap.com/docs/tools/pd-control/#config-show--set-option-value)
+    - Improve [PD simulator](https://github.com/pingcap/pd/tree/release-2.1/tools/pd-simulator) to simulate the scheduling scenarios
+
++ API and operation tools 
+    - Add the [`GetPrevRegion` interface](https://github.com/pingcap/kvproto/blob/8e3f33ac49297d7c93b61a955531191084a2f685/proto/pdpb.proto#L40) to support the `TiDB reverse scan` feature
+    - Add the [`BatchSplitRegion` interface](https://github.com/pingcap/kvproto/blob/8e3f33ac49297d7c93b61a955531191084a2f685/proto/pdpb.proto#L54) to speed up TiKV Region splitting
+    - Add the [`GCSafePoint` interface](https://github.com/pingcap/kvproto/blob/8e3f33ac49297d7c93b61a955531191084a2f685/proto/pdpb.proto#L64-L66) to support distributed GC in TiDB
+    - Add the [`GetAllStores` interface](https://github.com/pingcap/kvproto/blob/8e3f33ac49297d7c93b61a955531191084a2f685/proto/pdpb.proto#L32), to support distributed GC in TiDB
+    - pd-ctl supports:
+        - [using statistics for Region split](https://pingcap.com/docs/tools/pd-control/#operator-show--add--remove)
+        - [calling `jq` to format the JSON output](https://pingcap.com/docs/tools/pd-control/#jq-formatted-json-output-usage)
+        - [checking the Region information of the specified store](https://pingcap.com/docs/tools/pd-control/#region-store-store-id)
+        - [checking topN Region list sorted by versions](https://pingcap.com/docs/tools/pd-control/#region-topconfver-limit)
+        - [checking topN Region list sorted by size](https://pingcap.com/docs/tools/pd-control/#region-topsize-limit)
+        - [more precise TSO encoding](https://pingcap.com/docs/tools/pd-control/#tso)
+    - [pd-recover](https://pingcap.com/docs/tools/pd-recover) doesn't need to provide the `max-replica` parameter
+
++ Metrics
+    - Add related metrics for `Filter`
+    - Add metrics about etcd Raft state machine
+
++ Performance
+    - Optimize the performance of Region heartbeat to reduce the memory overhead brought by heartbeats
+    - Optimize the Region tree performance
+    - Optimize the performance of computing hotspot statistics
+
+## v2.1.0-rc.5
+- Fix the issues related to `pd-ctl` reading the Region key [#1298](https://github.com/pingcap/pd/pull/1298) [#1299](https://github.com/pingcap/pd/pull/1299) [#1308](https://github.com/pingcap/pd/pull/1308)
+- Fix the issue that the `regions/check` API returns the wrong result [#1311](https://github.com/pingcap/pd/pull/1311)
+- Fix the issue that PD cannot restart join after a PD join failure [#1279](https://github.com/pingcap/pd/pull/1279)
+- Fix the issue that `watch leader` might lose events in some cases [#1317](https://github.com/pingcap/pd/pull/1317)
+
+## v2.1.0-rc.4
+- Fix the issue that the tombstone TiKV is not removed from Grafana [#1261](https://github.com/pingcap/pd/pull/1261)
+- Fix the data race issue when grpc-go configures the status [#1265](https://github.com/pingcap/pd/pull/1265)
+- Fix the issue that the PD server gets stuck caused by etcd startup failure [#1267](https://github.com/pingcap/pd/pull/1267)
+- Fix the issue that data race might occur during leader switching [#1273](https://github.com/pingcap/pd/pull/1273)
+- Fix the issue that extra warning logs might be output when TiKV becomes tombstone [#1280](https://github.com/pingcap/pd/pull/1273)
+
+## v2.1.0-rc.3
+### New feature
+- Add the API to get the Region list by size in reverse order [#1254](https://github.com/pingcap/pd/pull/1254)
+### Improvement
+- Return more detailed information in the Region API [#1252](https://github.com/pingcap/pd/pull/1252)
+### Bug fix
+- Fix the issue that `adjacent-region-scheduler` might lead to a crash after PD switches the leader [#1250](https://github.com/pingcap/pd/pull/1250)
+
 ## v2.1.0-rc2
 ### Features
 * Support the `GetAllStores` interface

server/leader.go

@@ -284,7 +284,9 @@ func (s *Server) campaignLeader() error {
 				return nil
 			}
 		case <-ctx.Done():
-			return errors.New("server closed")
+			// Server is closed and it should return nil.
+			log.Info("server is closed")
+			return nil
 		}
 	}
 }