thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-11-22 07:31:57 +00:00
Code Issues Packages Projects Releases Wiki Activity

Update CHANGELOG.md

Browse Source
This commit is contained in:
alexey-milovidov 2019-09-18 23:32:10 +03:00 committed by GitHub
parent e17f54f5b5
commit 36075fd7c6
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
CHANGELOG.md
View File

@ -195,7 +195,7 @@
* Add Comments for set index functions. [#6319](https://github.com/yandex/ClickHouse/pull/6319) ([Nikita Vasilev](https://github.com/nikvas0))
### Performance Improvement
* Optimize queries with `ORDER BY expressions` clause, where `expressions` have coinciding prefix with sorting key in `MergeTree` tables. This optimization is enabled with `optimize_read_in_order` setting. [#6054](https://github.com/yandex/ClickHouse/pull/6054) [#6629](https://github.com/yandex/ClickHouse/pull/6629) ([Anton Popov](https://github.com/CurtizJ))
* Optimize queries with `ORDER BY expressions` clause, where `expressions` have coinciding prefix with sorting key in `MergeTree` tables. This optimization is controlled by `optimize_read_in_order` setting. [#6054](https://github.com/yandex/ClickHouse/pull/6054) [#6629](https://github.com/yandex/ClickHouse/pull/6629) ([Anton Popov](https://github.com/CurtizJ))
* Implemented batch variant of updating aggregate function states. It may lead to performance benefits. [#6435](https://github.com/yandex/ClickHouse/pull/6435) ([alexey-milovidov](https://github.com/alexey-milovidov))
* Using `FastOps` library for functions `exp`, `log`, `sigmoid`, `tanh`. FastOps is a fast vector math library from Michael Parakhin (Yandex CTO). Improved performance of `exp` and `log` functions more than 6 times. The functions `exp` and `log` from `Float32` argument will return `Float32` (in previous versions they always return `Float64`). Now `exp(nan)` may return `inf`. The result of `exp` and `log` functions may be not the nearest machine representable number to the true answer. [#6254](https://github.com/yandex/ClickHouse/pull/6254) ([alexey-milovidov](https://github.com/alexey-milovidov))
* Disable consecutive key optimization for `UInt8/16`. [#6298](https://github.com/yandex/ClickHouse/pull/6298) [#6701](https://github.com/yandex/ClickHouse/pull/6701) ([akuzm](https://github.com/akuzm))