releases, readme: add 2.1 RC3 release notes

README.md

@@ -135,6 +135,7 @@
 - [Frequently Asked Questions (FAQ)](FAQ.md)
 - [TiDB Best Practices](https://pingcap.github.io/blog/2017/07/24/tidbbestpractice/)
 + [Releases](releases/rn.md)
+  - [2.1 RC3](releases/21rc3.md)
   - [2.1 RC2](releases/21rc2.md)
   - [2.0.7](releases/207.md)
   - [2.1 RC1](releases/21rc1.md)

releases/21rc3.md

@@ -0,0 +1,63 @@
+---
+title: TiDB 2.1 RC3 Release Notes
+category: Releases
+---
+
+# TiDB 2.1 RC3 Release Notes
+
+On September 29, 2018, TiDB 2.1 RC3 is released. Compared with TiDB 2.1 RC2, this release has great improvement in stability, compatibility, SQL optimizer, and execution engine.
+
+## TiDB
+
++ SQL Optimizer
+    - Fix the incorrect result issue when a statement contains embedded `LEFT OUTER JOIN` [#7689](https://github.com/pingcap/tidb/pull/7689)
+    - Enhance the optimization rule of predicate pushdown on the `JOIN` statement [#7645](https://github.com/pingcap/tidb/pull/7645)
+    - Fix the optimization rule of predicate pushdown for the `UnionScan` operator [#7695](https://github.com/pingcap/tidb/pull/7695)
+    - Fix the issue that the unique key property of the `Union` operator is not correctly set [#7680](https://github.com/pingcap/tidb/pull/7680)
+    - Enhance the optimization rule of constant folding [#7696](https://github.com/pingcap/tidb/pull/7696)
+    - Optimize the data source in which the filter is null after propagation to table dual [#7756](https://github.com/pingcap/tidb/pull/7756)
++ SQL Execution Engine
+    - Optimize the performance of read requests in a transaction [#7717](https://github.com/pingcap/tidb/pull/7717)
+    - Optimize the cost of allocating Chunk memory in some executors [#7540](https://github.com/pingcap/tidb/pull/7540)
+    - Fix the "index out of range" panic caused by the columns where point queries get all NULL values [#7790](https://github.com/pingcap/tidb/pull/7790)
++ Server
+    - Fix the issue that the memory quota in the configuration file does not take effect [#7729](https://github.com/pingcap/tidb/pull/7729)
+    - Add the `tidb_force_priority` system variable to set the execution priority for each statement [#7694](https://github.com/pingcap/tidb/pull/7694)
+    - Support using the `admin show slow` statement to obtain the slow query log [#7785](https://github.com/pingcap/tidb/pull/7785)
++ Compatibility
+    - Fix the issue that the result of `charset/collation` is incorrect in `information_schema.schemata` [#7751](https://github.com/pingcap/tidb/pull/7751)
+    - Fix the issue that the value of the `hostname` system variable is empty [#7750](https://github.com/pingcap/tidb/pull/7750)
++ Expressions
+    - Support the `init_vecter` argument in the `AES_ENCRYPT`/`AES_DECRYPT` built-in function [#7425](https://github.com/pingcap/tidb/pull/7425)
+    - Fix the issue that the result of `Format` is incorrect in some expressions [#7770](https://github.com/pingcap/tidb/pull/7770)
+    - Support the `JSON_LENGTH` built-in function [#7739](https://github.com/pingcap/tidb/pull/7739)
+    - Fix the incorrect result issue when casting the unsigned integer type to the decimal type [#7792](https://github.com/pingcap/tidb/pull/7792)
++ DML
+    - Fix the issue that the result of the `INSERT … ON DUPLICATE KEY UPDATE` statement is incorrect while updating the unique key [#7675](https://github.com/pingcap/tidb/pull/7675)
++ DDL
+    - Fix the issue that the index value is not converted between time zones when you create a new index on a new column of the timestamp type [#7724](https://github.com/pingcap/tidb/pull/7724)
+    - Support appending new values for the enum type [#7767](https://github.com/pingcap/tidb/pull/7767)
+    - Support creating an etcd session quickly, which improves the cluster availability after network isolation [#7774](https://github.com/pingcap/tidb/pull/7774)
+
+## PD
+
++ 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)
+
+## TiKV
+
++ Performance
+    - Optimize the concurrency for coprocessor requests [#3515](https://github.com/tikv/tikv/pull/3515)
++ New features
+    - Add the support for Log functions [#3603](https://github.com/tikv/tikv/pull/3603)
+    - Add the support for the `sha1` function [#3612](https://github.com/tikv/tikv/pull/3612)
+    - Add the support for the `truncate_int` function [#3532](https://github.com/tikv/tikv/pull/3532)
+    - Add the support for the `year` function [#3622](https://github.com/tikv/tikv/pull/3622)
+    - Add the support for the `truncate_real` function [#3633](https://github.com/tikv/tikv/pull/3633)
++ Bug fixes
+    - Fix the reporting error behavior related to time functions [#3487](https://github.com/tikv/tikv/pull/3487), [#3615](https://github.com/tikv/tikv/pull/3615)
+    - Fix the issue that the time parsed from string is inconsistent with that in TiDB [#3589](https://github.com/tikv/tikv/pull/3589)

releases/rn.md

@@ -5,6 +5,7 @@ category: release
 
 # TiDB Release Notes
 
+  - [2.1 RC3](21rc3.md)
   - [2.1 RC2](21rc2.md)
   - [2.0.7](207.md)
   - [2.1 RC1](21rc1.md)