releases, readme: add the release notes for 2.0.5 (#522)

README.md

@@ -129,6 +129,7 @@
 - [Frequently Asked Questions (FAQ)](FAQ.md)
 - [TiDB Best Practices](https://pingcap.github.io/blog/2017/07/24/tidbbestpractice/)
 + [Releases](releases/rn.md)
+  - [2.0.5](releases/205.md)
   - [2.1 Beta](releases/21beta.md)
   - [2.0.4](releases/204.md)
   - [2.0.3](releases/203.md)

releases/205.md

@@ -0,0 +1,40 @@
+---
+title: TiDB 2.0.5 Release Notes
+category: Releases
+---
+
+# TiDB 2.0.5 Release Notes
+
+On July 6, 2018, TiDB 2.0.5 is released. Compared with TiDB 2.0.4, this release has great improvement in system compatibility and stability.
+
+## TiDB
+
+- New Features
+    - Add the `tidb_disable_txn_auto_retry` system variable which is used to disable the automatic retry of transactions [#6877](https://github.com/pingcap/tidb/pull/6877)
+- Improvements
+    - Optimize the cost calculation of `Selection` to make the result more accurate [#6989](https://github.com/pingcap/tidb/pull/6989)
+    - Select the query condition that completely matches the unique index or the primary key as the query path directly [#6966](https://github.com/pingcap/tidb/pull/6966)
+    - Execute necessary cleanup when failing to start the service [#6964](https://github.com/pingcap/tidb/pull/6964)
+    - Handle `\N` as NULL in the `Load Data` statement [#6962](https://github.com/pingcap/tidb/pull/6962)
+    - Optimize the code structure of CBO [#6953](https://github.com/pingcap/tidb/pull/6953)
+    - Report the monitoring metrics earlier when starting the service [#6931](https://github.com/pingcap/tidb/pull/6931)
+    - Optimize the format of slow queries by removing the line breaks in SQL statements and adding user information [#6920](https://github.com/pingcap/tidb/pull/6920)
+    - Support multiple asterisks in comments [#6858](https://github.com/pingcap/tidb/pull/6858)
+- Bug Fixes
+    - Fix the issue that `KILL QUERY` always requires SUPER privilege [#7003](https://github.com/pingcap/tidb/pull/7003)
+    - Fix the issue that users might fail to login when the number of users exceeds 1024 [#6986](https://github.com/pingcap/tidb/pull/6986)
+    - Fix an issue about inserting unsigned `float`/`double` data [#6940](https://github.com/pingcap/tidb/pull/6940)
+    - Fix the compatibility of the `COM_FIELD_LIST` command to resolve the panic issue in some MariaDB clients [#6929](https://github.com/pingcap/tidb/pull/6929)
+    - Fix the `CREATE TABLE IF NOT EXISTS LIKE` behavior [#6928](https://github.com/pingcap/tidb/pull/6928)
+    - Fix an issue in the process of TopN pushdown [#6923](https://github.com/pingcap/tidb/pull/6923)
+    - Fix the ID record issue of the currently processing row when an error occurs in executing `Add Index` [#6903](https://github.com/pingcap/tidb/pull/6903)
+
+## PD
+
+- Fix the issue that replicas migration uses up TiKV disks space in some scenarios
+- Fix the crash issue caused by `AdjacentRegionScheduler`
+
+## TiKV
+
+- Fix the potential overflow issue in decimal operations
+- Fix the dirty read issue that might occur in the process of merging

releases/rn.md

@@ -5,6 +5,7 @@ category: release
 
 # TiDB Release Notes
 
+  - [2.0.5](205.md)
   - [2.1 Beta](21beta.md)
   - [2.0.4](204.md)
   - [2.0.3](203.md)