releases, readme: add TiDB 2.1.1 Release Notes (pingcap#809)

README.md

@@ -156,6 +156,7 @@
 - [Frequently Asked Questions (FAQ)](FAQ.md)
 - [TiDB Best Practices](https://pingcap.com/blog/2017-07-24-tidbbestpractice/)
 + [Releases](releases/rn.md)
+  - [2.1.1](releases/2.1.1.md)
   - [2.1 GA](releases/2.1ga.md)
   - [2.0.9](releases/209.md)
   - [2.1 RC5](releases/21rc5.md)

releases/2.1.1.md

@@ -0,0 +1,46 @@
+---
+title: TiDB 2.1.1 Release Notes
+category: Releases
+---
+
+# TiDB 2.1.1 Release Notes
+
+On December 12, 2018, TiDB 2.1.1 is released. Compared with TiDB 2.1.0, this release has great improvement in stability, SQL optimizer, statistics information, and execution engine.
+
+## TiDB
+
++ SQL Optimizer/Executor
+    - Fix the round error of the negative date [#8574](https://github.com/pingcap/tidb/pull/8574)
+    - Fix the issue that the `uncompress` function does not check the data length [#8606](https://github.com/pingcap/tidb/pull/8606)
+    - Reset bind arguments of the `prepare` statement after the `execute` command is executed [#8652](https://github.com/pingcap/tidb/pull/8652)
+    - Support automatically collecting the statistics information of a partition table [#8649](https://github.com/pingcap/tidb/pull/8649)
+    - Fix the wrongly configured integer type when pushing down the `abs` function [#8628](https://github.com/pingcap/tidb/pull/8628)
+    - Fix the data race on the JSON column [#8660](https://github.com/pingcap/tidb/pull/8660) 
++ Server
+    - Fix the issue that the transaction obtained TSO is incorrect when PD breaks down [#8567](https://github.com/pingcap/tidb/pull/8567)
+    - Fix the bootstrap failure caused by the statement that does not conform to ANSI standards [#8576](https://github.com/pingcap/tidb/pull/8576)
+    - Fix the issue that incorrect parameters are used in transaction retries [#8638](https://github.com/pingcap/tidb/pull/8638)
++ DDL
+    - Change the default character set and collation of tables into `utf8mb4` [#8590](https://github.com/pingcap/tidb/pull/8590)
+    - Add the `ddl_reorg_batch_size` variable to control the speed of adding indexes [#8614](https://github.com/pingcap/tidb/pull/8614)
+    - Make the character set and collation options content in DDL case-insensitive [#8611](https://github.com/pingcap/tidb/pull/8611)
+    - Fix the issue of adding indexes for generated columns [#8655](https://github.com/pingcap/tidb/pull/8655)
+
+## PD
+
+- 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)
+
+## TiKV
+
+- Avoid transferring the leader to a newly created peer, to optimize the possible delay [#3878](https://github.com/tikv/tikv/pull/3878)
+
+## Tools
+
++ Lightning
+    - Optimize the `analyze` mechanism on imported tables to increase the import speed
+    - Support storing the checkpoint information to a local file
++ TiDB-Binlog
+    - Fix the output bug of pb files that a table only with the primary key column cannot generate the pb event

releases/rn.md

@@ -5,6 +5,7 @@ category: release
 
 # TiDB Release Notes
 
+- [2.1.1](../releases/2.1.1.md)
 - [2.1 GA](../releases/2.1ga.md)
 - [2.0.9](../releases/209.md)
 - [2.1 RC5](../releases/21rc5.md)