docs: update README and CHANGELOG (#1058)

CHANGELOG.md

@@ -1,14 +1,67 @@
 # Changelog
 
-## [Unreleased]
-### Feature
-- Support insert multiple rows into a table using a single SQL insert statement. [#398](https://github.com/4paradigm/OpenMLDB/issues/398)
-- Support aggregation function, e.g. `COUNT`, `SUM`, `MIN`, `MAX`, `AVG`, over the whole table [#219](https://github.com/4paradigm/OpenMLDB/issues/219)
-- Enhance plan optimization on `GROUP` and `FILTER` op [#350](https://github.com/4paradigm/OpenMLDB/pull/350)
-- Refactor status code and status macro. Save first message (root message) in `status.msg`. [#430](https://github.com/4paradigm/OpenMLDB/issues/430)
+## [0.4.0] - 2022-01-14
+
+### Highlights
+
+- The SQL-centric feature is enhanced for both standalone and cluster versions. Now you can enjoy the SQL-centric development and deployment experience seamlessly. (#991,#1034,#1071,#1064,#1061,#1049,#1045,#1038,#1034,#1029,#997,#996,#968,#946,#840,#830,#814,#776,#774,#764,#747,#740,#466,#481,#1033,#1027,#966,#951,#950,#932,#853,#835,#804,#800,#596,#595,#568,#873,#1025,#1021,#1019,#994,#991,#987,#912,#896,#894,#893,#873,#778,#777,#745,#737,#701,#570,#559,#558,#553 @tobegit3hub; #1030,#965,#933,#920,#829,#783,#754,#1005,#998 @vagetablechicken)
+- The Chinese documentations are thoroughly polished and accessible at https://docs.openmldb.ai/ . This documentation repository is available at https://github.com/4paradigm/openmldb-docs-zh , and you are welcome to make contributions.
+- Experimental feature: We have introduced a monitoring module based on Prometheus + Grafana for online feature processing. (#1048 @aceforeverd)
+
+### Other Features
+
+- Support SQL syntax: LIKE, HAVING (#841 @aceforeverd; #927,#698 @jingchen2222)
+- Support new built-in functions: reverse (#1004 @nautaa), dayofyear (#856 @Nicholas-SR)
+- Improve the compilation and install process, and support building from sources (#999,#871,#594,#752,#793,#805,#875,#871,#999 @aceforeverd; #992 @vagetablechicken)
+- Improve the GitHub CI/CD workflow (#842,#884,#875,#919,#1056,#874 @aceforeverd)
+- Support system databases and tables (#773 @dl239)
+- Improve the function `create index` (#828 @dl239)
+- Improve the demo image (#1023,#690,#734,#751 @zhanghaohit)
+- Improve the Python SDK (#913,#906 @tobegit3hub;#949,#909 @HuilinWu2; #838 @dl239)
+- Simplify the concepts of execution modes (#877,#985,#892 @jingchen2222)
+- Add data import and export for the cluster version (#1078 @tobegit3hub)
+- Add new deployment command for the cluster version (#921 @dl239)
+- Support default values when creating a table (#563 @zoyopei)
+- Support string delimiters and quotes (#668 @ZackeryWang)
+- Add a new `lru_cache` to support upsert (#795 @vagetablechicken)
+- Support adding index with any `ts_col` (#828 @dl239)
+- Improve the `ts` packing in `sql_insert_now` (#955,#938 @vagetablechicken)
+- Improve documentations (#952 #885 @mahengyang; #834 @Nicholas-SR; #792,#1058,#1002,#872,#836,#792 @lumianph; #844,#782 @jingchen2222; #1022,#805 @aceforeverd)
+- Other minor updates (#1073 @dl239)
+
+### Bug Fixes
+
+#847, #831, #647, #934, #953, #1015, #982, #927, #994, #1008, #1028, #1019, #779, #855, #350, #631, #1074, #1073, #1081
+
+@nautaa, @Nicholas-SR, @aceforeverd, @dl239, @jingchen2222, @tobegit3hub, @keyu813
+
+
+
+## [0.3.0] - 2021-11-05
+
+### Highlights
+We introduce a new standalone mode that can be deployed on a single node, which is suitable for small businesses and the demonstration purpose. Please read more details from [here](https://github.com/4paradigm/OpenMLDB/blob/v0.3.0/docs/en/standalone.md). The standalone mode is particularly enhanced for ease of use based on the following features that are supported by standalone mode only.
+* The standalone deployment mode https://github.com/4paradigm/OpenMLDB/issues/440
+* Connection establishment by specifying the host name and port in CLI https://github.com/4paradigm/OpenMLDB/issues/441
+* LOAD DATA command for bulk loading https://github.com/4paradigm/OpenMLDB/issues/443
+* SQL syntax support for exporting data: SELECT INTO FILE https://github.com/4paradigm/OpenMLDB/issues/455
+* Deployment commands: DEPLOY, SHOW DEPLOYMENT, and DROP DEPLOYMENT https://github.com/4paradigm/OpenMLDB/issues/460 https://github.com/4paradigm/OpenMLDB/issues/447
+### Other Features
+* A new CLI command to support different levels of performance sensitivity:  `SET performance_sensitive=true|false`. When it is set to false, SQL queries can be executed without indexes. Please read [here](https://github.com/4paradigm/OpenMLDB/blob/v0.3.0/docs/en/performance_sensitive_mode.md) for more details about the performance sensitivity configuration https://github.com/4paradigm/OpenMLDB/issues/555
+* Supporting SQL queries over multiple databases https://github.com/4paradigm/OpenMLDB/issues/476
+* Supporting inserting multiple tuples into a table using a single SQL https://github.com/4paradigm/OpenMLDB/issues/398
+* Improvements for Java SDK:
+The new API getTableSchema https://github.com/4paradigm/OpenMLDB/pull/483
+The new API genDDL, which is used to generate DDLs according to a given SQL script https://github.com/4paradigm/OpenMLDB/issues/588
+### Bugfix
+* Exceptions caused by certain physical plans with special structures when performing column resolve for logical plans. https://github.com/4paradigm/OpenMLDB/issues/437
+* Under specific circumstances, unexpected outcomes produced by SQL queries with the WHERE when certain WHERE conditions do not fit into indexes https://github.com/4paradigm/OpenMLDB/issues/599
+* The bug when enabling WindowParallelOpt and WindowSkewOptimization at the same times https://github.com/4paradigm/OpenMLDB/issues/444
+* The bug of LCA (Lowest Common Ancestor) algorithm to support WindowParallelOpt for particular SQLs https://github.com/4paradigm/OpenMLDB/issues/485
+* Workaround for the Spark bug (SPARK-36932) when the columns with the same names in LastJoin https://github.com/4paradigm/OpenMLDB/issues/484
+### Acknowledgement
+We appreciate the contribution to this release from external contributors who are not from 4Paradigm's core OpenMLDB team, including [Kanekanekane](https://github.com/Kanekanekane), [shawn-happy](https://github.com/shawn-happy), [lotabout](https://github.com/lotabout), [Shouren](https://github.com/Shouren), [zoyopei](https://github.com/zoyopei), [huqianshan](https://github.com/huqianshan)
 
-### Bug Fix
-- Fix plan error triggered by optimize the same plan node repeatedly. [#437](https://github.com/4paradigm/OpenMLDB/issues/437)
 
 ## [0.2.3] - 2021-08-31
 ### Feature
@@ -60,7 +113,8 @@ Removed
 - openmldb-0.2.0-linux.tar.gz targets on x86_64
 - aarch64 artifacts consider experimental
 
-[Unreleased]: https://github.com/4paradigm/OpenMLDB/compare/v0.2.3...HEAD
+[0.4.0]: https://github.com/4paradigm/OpenMLDB/compare/v0.3.0...v0.4.0
+[0.3.0]: https://github.com/4paradigm/OpenMLDB/compare/v0.2.3...v0.3.0
 [0.2.3]: https://github.com/4paradigm/OpenMLDB/compare/0.2.2...v0.2.3
 [0.2.2]: https://github.com/4paradigm/OpenMLDB/compare/v0.2.0...0.2.2
 [0.2.0]: https://github.com/4paradigm/OpenMLDB/compare/v0.1.5-pre...v0.2.0