@@ -372,7 +372,7 @@ It allows to set commit mode: after every batch of messages is handled, or after
* Renamed functions `leastSqr` to `simpleLinearRegression`, `LinearRegression` to `linearRegression`, `LogisticRegression` to `logisticRegression`. [#5391](https://github.com/yandex/ClickHouse/pull/5391)([Nikolai Kochetov](https://github.com/KochetovNicolai))
### Performance Improvements
* Paralellize processing of parts of non-replicated MergeTree tables in ALTER MODIFY query. [#4639](https://github.com/yandex/ClickHouse/pull/4639)([Ivan Kush](https://github.com/IvanKush))
* Parallelize processing of parts of non-replicated MergeTree tables in ALTER MODIFY query. [#4639](https://github.com/yandex/ClickHouse/pull/4639)([Ivan Kush](https://github.com/IvanKush))
* Optimizations in regular expressions extraction. [#5193](https://github.com/yandex/ClickHouse/pull/5193)[#5191](https://github.com/yandex/ClickHouse/pull/5191) ([Danila Kutenin](https://github.com/danlark1))
* Do not add right join key column to join result if it's used only in join on section. [#5260](https://github.com/yandex/ClickHouse/pull/5260)([Artem Zuikov](https://github.com/4ertus2))
* Freeze the Kafka buffer after first empty response. It avoids multiple invokations of `ReadBuffer::next()` for empty result in some row-parsing streams. [#5283](https://github.com/yandex/ClickHouse/pull/5283)([Ivan](https://github.com/abyss7))
* Wrong arguments to `hasAny` or `hasAll` functions may lead to segfault. [#4698](https://github.com/yandex/ClickHouse/pull/4698)([alexey-milovidov](https://github.com/alexey-milovidov))
* Deadlock may happen while executing `DROP DATABASE dictionary` query. [#4701](https://github.com/yandex/ClickHouse/pull/4701)([alexey-milovidov](https://github.com/alexey-milovidov))
* Fix undefinied behavior in `median` and `quantile` functions. [#4702](https://github.com/yandex/ClickHouse/pull/4702)([hcz](https://github.com/hczhcz))
* Fix undefined behavior in `median` and `quantile` functions. [#4702](https://github.com/yandex/ClickHouse/pull/4702)([hcz](https://github.com/hczhcz))
* Fix compression level detection when `network_compression_method` in lowercase. Broken in v19.1. [#4706](https://github.com/yandex/ClickHouse/pull/4706)([proller](https://github.com/proller))
* Fixed ignorance of `<timezone>UTC</timezone>` setting (fixes issue [#4658](https://github.com/yandex/ClickHouse/issues/4658)). [#4718](https://github.com/yandex/ClickHouse/pull/4718)([proller](https://github.com/proller))
* Fix `histogram` function behaviour with `Distributed` tables. [#4741](https://github.com/yandex/ClickHouse/pull/4741)([olegkv](https://github.com/olegkv))
* Wrong arguments to `hasAny` or `hasAll` functions may lead to segfault. [#4698](https://github.com/yandex/ClickHouse/pull/4698)([alexey-milovidov](https://github.com/alexey-milovidov))
* Deadlock may happen while executing `DROP DATABASE dictionary` query. [#4701](https://github.com/yandex/ClickHouse/pull/4701)([alexey-milovidov](https://github.com/alexey-milovidov))
* Fix undefinied behavior in `median` and `quantile` functions. [#4702](https://github.com/yandex/ClickHouse/pull/4702)([hcz](https://github.com/hczhcz))
* Fix undefined behavior in `median` and `quantile` functions. [#4702](https://github.com/yandex/ClickHouse/pull/4702)([hcz](https://github.com/hczhcz))
* Fix compression level detection when `network_compression_method` in lowercase. Broken in v19.1. [#4706](https://github.com/yandex/ClickHouse/pull/4706)([proller](https://github.com/proller))
* Fixed ignorance of `<timezone>UTC</timezone>` setting (fixes issue [#4658](https://github.com/yandex/ClickHouse/issues/4658)). [#4718](https://github.com/yandex/ClickHouse/pull/4718)([proller](https://github.com/proller))
* Fix `histogram` function behaviour with `Distributed` tables. [#4741](https://github.com/yandex/ClickHouse/pull/4741)([olegkv](https://github.com/olegkv))
* Added aggregate function `entropy` which computes Shannon entropy. [#4238](https://github.com/yandex/ClickHouse/pull/4238)([Quid37](https://github.com/Quid37))
* Added ability to send queries `INSERT INTO tbl VALUES (....` to server without splitting on `query` and `data` parts. [#4301](https://github.com/yandex/ClickHouse/pull/4301)([alesapin](https://github.com/alesapin))
* Generic implementation of `arrayWithConstant` function was added. [#4322](https://github.com/yandex/ClickHouse/pull/4322)([alexey-milovidov](https://github.com/alexey-milovidov))
* Implement `sumMapFiltered` in order to be able to limit the number of keys for which values will be summed by `sumMap`. [#4129](https://github.com/yandex/ClickHouse/pull/4129)([Léo Ercolanelli](https://github.com/ercolanelli-leo))
* Added support of `Nullable` types in `mysql` table function. [#4198](https://github.com/yandex/ClickHouse/pull/4198)([Emmanuel Donin de Rosière](https://github.com/edonin))
* Support for arbitrary constant expressions in `LIMIT` clause. [#4246](https://github.com/yandex/ClickHouse/pull/4246)([k3box](https://github.com/k3box))
* Added keyword `INDEX` in `CREATE TABLE` query. A column with name `index` must be quoted with backticks or double quotes: `` `index` ``. [#4143](https://github.com/yandex/ClickHouse/pull/4143)([Nikita Vasilev](https://github.com/nikvas0))
*`sumMap` now promote result type instead of overflow. The old `sumMap` behavior can be obtained by using `sumMapWithOverflow` function. [#4151](https://github.com/yandex/ClickHouse/pull/4151)([Léo Ercolanelli](https://github.com/ercolanelli-leo))
### Performance Impovements
### Performance Improvements
*`std::sort` replaced by `pdqsort` for queries without `LIMIT`. [#4236](https://github.com/yandex/ClickHouse/pull/4236)([Evgenii Pravda](https://github.com/kvinty))
* Now server reuse threads from global thread pool. This affects performance in some corner cases. [#4150](https://github.com/yandex/ClickHouse/pull/4150)([alexey-milovidov](https://github.com/alexey-milovidov))