releases: add tidb 3.0.20 release notes (#4421)

* update v3.0.20 release notes at 2020-12-16T18:16:18

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

* add toc

* Apply suggestions from code review

Co-authored-by: Feng Liyuan <darktemplar.f@gmail.com>

* Update release-3.0.20.md

* Update release-3.0.20.md

* Update release-3.0.20.md

* Update release-3.0.20.md

* Update releases/release-3.0.20.md

* Update releases/release-3.0.20.md

* Update releases/release-3.0.20.md

Co-authored-by: TomShawn <41534398+TomShawn@users.noreply.github.com>
Co-authored-by: Feng Liyuan <darktemplar.f@gmail.com>

TOC.md

@@ -554,6 +554,7 @@
     + [3.1.0-beta.1](/releases/release-3.1.0-beta.1.md)
     + [3.1.0-beta](/releases/release-3.1.0-beta.md)
   + v3.0
+    + [3.0.20](/releases/release-3.0.20.md)
     + [3.0.19](/releases/release-3.0.19.md)
     + [3.0.18](/releases/release-3.0.18.md)
     + [3.0.17](/releases/release-3.0.17.md)

releases/release-3.0.20.md

@@ -0,0 +1,60 @@
+---
+title: TiDB 3.0.20 Release Notes
+---
+
+# TiDB 3.0.20 Release Notes
+
+Release date: December 25, 2020
+
+TiDB version: 3.0.20
+
+## Compatibility Change
+
++ TiDB
+
+    - Deprecate the `enable-streaming` configuration item [#21054](https://github.com/pingcap/tidb/pull/21054)
+
+## Improvements
+
++ TiDB
+
+    - Raise an error when preparing the `LOAD DATA` statement [#21222](https://github.com/pingcap/tidb/pull/21222)
+
++ TiKV
+
+    - Add the `end_point_slow_log_threshold` configuration item [#9145](https://github.com/tikv/tikv/pull/9145)
+
+## Bug Fixes
+
++ TiDB
+
+    - Fix the incorrect cache of the transaction status for pessimistic transactions [#21706](https://github.com/pingcap/tidb/pull/21706)
+    - Fix the issue of inaccurate statistics that occurs when querying `INFORMATION_SCHEMA.TIDB_HOT_REGIONS` [#21319](https://github.com/pingcap/tidb/pull/21319)
+[#21222](https://github.com/pingcap/tidb/pull/21222)
+    - Fix the issue that `DELETE` might not delete data correctly when the database name is not in a pure lower representation [#21205](https://github.com/pingcap/tidb/pull/21205)
+    - Fix the issue of stack overflow that occurs when building the recursive view [#21000](https://github.com/pingcap/tidb/pull/21000)
+    - Fix the issue of goroutine leak in TiKV client [#20863](https://github.com/pingcap/tidb/pull/20863)
+    - Fix the wrong default zero value for the `year` type [#20828](https://github.com/pingcap/tidb/pull/20828)
+    - Fix the issue of goroutine leak in index lookup join [#20791](https://github.com/pingcap/tidb/pull/20791)
+    - Fix the issue that executing `INSERT SELECT FOR UPDATE` returns the malformed packet in the pessimistic transaction [#20681](https://github.com/pingcap/tidb/pull/20681)
+    - Fix the unknown time zone `'posixrules'` [#20605](https://github.com/pingcap/tidb/pull/20605)
+    - Fix the issue that occurs when converting the unsigned integer type to the bit type [#20362](https://github.com/pingcap/tidb/pull/20362)
+    - Fix the corrupted default value of the bit type column [#20339](https://github.com/pingcap/tidb/pull/20339)
+    - Fix the potentially incorrect results when one of the equal condition is the `Enum` or `Set` type [#20296](https://github.com/pingcap/tidb/pull/20296)
+    - Fix a wrong behavior of `!= any()` [#20061](https://github.com/pingcap/tidb/pull/20061)
+    - Fix the issue that type conversion in `BETWEEN...AND...` returns invalid results [#21503](https://github.com/pingcap/tidb/pull/21503)
+    - Fix a compatibility issue with the `ADDDATE` function [#21008](https://github.com/pingcap/tidb/pull/21008)
+    - Set the correct default value for newly added `Enum` column [#20999](https://github.com/pingcap/tidb/pull/20999)
+    - Fix the result of SQL statements like `SELECT DATE_ADD('2007-03-28 22:08:28',INTERVAL "-2.-2" SECOND)` to be compatible with MySQL [#20627](https://github.com/pingcap/tidb/pull/20627)
+    - Fix the incorrect default value when modifying the column type [#20532](https://github.com/pingcap/tidb/pull/20532)
+    - Fix the issue that the `timestamp` function gets wrong result when the input argument is the `float` or `decimal` type [#20469](https://github.com/pingcap/tidb/pull/20469)
+    - Fix a potential deadlock issue in statistics [#20424](https://github.com/pingcap/tidb/pull/20424)
+    - Fix the issue that the overflown float type data is inserted [#20251](https://github.com/pingcap/tidb/pull/20251)
+
++ TiKV
+
+    - Fix the issue that an error is returned indicating that a key exists when this key is locked and deleted in a committed transaction [#8931](https://github.com/tikv/tikv/pull/8931)
+
++ PD
+
+    - Fix the issue that too many logs are printed when starting PD and when there are too many stale Regions [#3064](https://github.com/pingcap/pd/pull/3064)

releases/release-notes.md

@@ -36,6 +36,7 @@ aliases: ['/docs/dev/releases/release-notes/','/docs/dev/releases/rn/']
 
 ## 3.0
 
+- [3.0.20](/releases/release-3.0.20.md)
 - [3.0.19](/releases/release-3.0.19.md)
 - [3.0.18](/releases/release-3.0.18.md)
 - [3.0.17](/releases/release-3.0.17.md)