title_wip

#### Performance Improvement[​](#performance-improvement-7 "Direct link to Performance Improvement")

- Improve performance of `avg`, `sum` aggregate functions if used without GROUP BY expression. [#37257](https://github.com/ClickHouse/ClickHouse/pull/37257) ([Maksim Kita](https://github.com/kitaisreal)).
- Improve performance of unary arithmetic functions (`bitCount`, `bitNot`, `abs`, `intExp2`, `intExp10`, `negate`, `roundAge`, `roundDuration`, `roundToExp2`, `sign`) using dynamic dispatch. [#37289](https://github.com/ClickHouse/ClickHouse/pull/37289) ([Maksim Kita](https://github.com/kitaisreal)).
- Improve performance of ORDER BY, MergeJoin, insertion into MergeTree using JIT compilation of sort columns comparator. [#34469](https://github.com/ClickHouse/ClickHouse/pull/34469) ([Maksim Kita](https://github.com/kitaisreal)).
- Change structure of `system.asynchronous_metric_log`. It will take about 10 times less space. This closes [#36357](https://github.com/ClickHouse/ClickHouse/issues/36357). The field `event_time_microseconds` was removed, because it is useless. [#36360](https://github.com/ClickHouse/ClickHouse/pull/36360) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Load marks for only necessary columns when reading wide parts. [#36879](https://github.com/ClickHouse/ClickHouse/pull/36879) ([Anton Kozlov](https://github.com/tonickkozlov)).
- Improves performance of file descriptor cache by narrowing mutex scopes. [#36682](https://github.com/ClickHouse/ClickHouse/pull/36682) ([Anton Kozlov](https://github.com/tonickkozlov)).
- Improve performance of reading from storage `File` and table functions `file` in case when path has globs and matched directory contains large number of files. [#36647](https://github.com/ClickHouse/ClickHouse/pull/36647) ([Anton Popov](https://github.com/CurtizJ)).
- Apply parallel parsing for input format `HiveText`, which can speed up HiveText parsing by 2x when reading local file. [#36650](https://github.com/ClickHouse/ClickHouse/pull/36650) ([李扬](https://github.com/taiyang-li)).
- The default `HashJoin` is not thread safe for inserting right table's rows and run it in a single thread. When the right table is large, the join process is too slow with low cpu utilization. [#36415](https://github.com/ClickHouse/ClickHouse/pull/36415) ([lgbo](https://github.com/lgbo-ustc)).
- Allow to rewrite `select countDistinct(a) from t` to `select count(1) from (select a from t groupBy a)`. [#35993](https://github.com/ClickHouse/ClickHouse/pull/35993) ([zhanglistar](https://github.com/zhanglistar)).
- Transform OR LIKE chain to multiMatchAny. Will enable once we have more confidence it works. [#34932](https://github.com/ClickHouse/ClickHouse/pull/34932) ([Daniel Kutenin](https://github.com/danlark1)).
- Improve performance of some functions with inlining. [#34544](https://github.com/ClickHouse/ClickHouse/pull/34544) ([Daniel Kutenin](https://github.com/danlark1)).
- Add a branch to avoid unnecessary memcpy in readBig. It improves performance somewhat. [#36095](https://github.com/ClickHouse/ClickHouse/pull/36095) ([jasperzhu](https://github.com/jinjunzh)).
- Implement partial GROUP BY key for optimize\_aggregation\_in\_order. [#35111](https://github.com/ClickHouse/ClickHouse/pull/35111) ([Azat Khuzhin](https://github.com/azat)).

#### Improvement[​](#improvement-7 "Direct link to Improvement")