2019 Changelog

#### Build/Testing/Packaging Improvements[​](#buildtestingpackaging-improvements-5 "Direct link to Build/Testing/Packaging Improvements")

- Debian package: correct /etc/clickhouse-server/preprocessed link according to config. [#4205](https://github.com/ClickHouse/ClickHouse/pull/4205) ([proller](https://github.com/proller))
- Various build fixes for FreeBSD. [#4225](https://github.com/ClickHouse/ClickHouse/pull/4225) ([proller](https://github.com/proller))
- Added ability to create, fill and drop tables in perftest. [#4220](https://github.com/ClickHouse/ClickHouse/pull/4220) ([alesapin](https://github.com/alesapin))
- Added a script to check for duplicate includes. [#4326](https://github.com/ClickHouse/ClickHouse/pull/4326) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Added ability to run queries by index in performance test. [#4264](https://github.com/ClickHouse/ClickHouse/pull/4264) ([alesapin](https://github.com/alesapin))
- Package with debug symbols is suggested to be installed. [#4274](https://github.com/ClickHouse/ClickHouse/pull/4274) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Refactoring of performance-test. Better logging and signals handling. [#4171](https://github.com/ClickHouse/ClickHouse/pull/4171) ([alesapin](https://github.com/alesapin))
- Added docs to anonymized Yandex.Metrica datasets. [#4164](https://github.com/ClickHouse/ClickHouse/pull/4164) ([alesapin](https://github.com/alesapin))
- Аdded tool for converting an old month-partitioned part to the custom-partitioned format. [#4195](https://github.com/ClickHouse/ClickHouse/pull/4195) ([Alex Zatelepin](https://github.com/ztlpn))
- Added docs about two datasets in s3. [#4144](https://github.com/ClickHouse/ClickHouse/pull/4144) ([alesapin](https://github.com/alesapin))
- Added script which creates changelog from pull requests description. [#4169](https://github.com/ClickHouse/ClickHouse/pull/4169) [#4173](https://github.com/ClickHouse/ClickHouse/pull/4173) ([KochetovNicolai](https://github.com/KochetovNicolai)) ([KochetovNicolai](https://github.com/KochetovNicolai))
- Added puppet module for ClickHouse. [#4182](https://github.com/ClickHouse/ClickHouse/pull/4182) ([Maxim Fedotov](https://github.com/MaxFedotov))
- Added docs for a group of undocumented functions. [#4168](https://github.com/ClickHouse/ClickHouse/pull/4168) ([Winter Zhang](https://github.com/zhang2014))
- ARM build fixes. [#4210](https://github.com/ClickHouse/ClickHouse/pull/4210)[#4306](https://github.com/ClickHouse/ClickHouse/pull/4306) [#4291](https://github.com/ClickHouse/ClickHouse/pull/4291) ([proller](https://github.com/proller)) ([proller](https://github.com/proller))
- Dictionary tests now able to run from `ctest`. [#4189](https://github.com/ClickHouse/ClickHouse/pull/4189) ([proller](https://github.com/proller))
- Now `/etc/ssl` is used as default directory with SSL certificates. [#4167](https://github.com/ClickHouse/ClickHouse/pull/4167) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Added checking SSE and AVX instruction at start. [#4234](https://github.com/ClickHouse/ClickHouse/pull/4234) ([Igr](https://github.com/igron99))
- Init script will wait server until start. [#4281](https://github.com/ClickHouse/ClickHouse/pull/4281) ([proller](https://github.com/proller))

#### Backward Incompatible Changes[​](#backward-incompatible-changes-1 "Direct link to Backward Incompatible Changes")

- Removed `allow_experimental_low_cardinality_type` setting. `LowCardinality` data types are production ready. [#4323](https://github.com/ClickHouse/ClickHouse/pull/4323) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Reduce mark cache size and uncompressed cache size accordingly to available memory amount. [#4240](https://github.com/ClickHouse/ClickHouse/pull/4240) ([Lopatin Konstantin](https://github.com/k-lopatin)
- 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/ClickHouse/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/ClickHouse/ClickHouse/pull/4151) ([Léo Ercolanelli](https://github.com/ercolanelli-leo))

#### Performance Improvements[​](#performance-improvements-4 "Direct link to Performance Improvements")

- `std::sort` replaced by `pdqsort` for queries without `LIMIT`. [#4236](https://github.com/ClickHouse/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/ClickHouse/ClickHouse/pull/4150) ([alexey-milovidov](https://github.com/alexey-milovidov))

#### Improvements[​](#improvements-5 "Direct link to Improvements")

- Implemented AIO support for FreeBSD. [#4305](https://github.com/ClickHouse/ClickHouse/pull/4305) ([urgordeadbeef](https://github.com/urgordeadbeef))
- `SELECT * FROM a JOIN b USING a, b` now return `a` and `b` columns only from the left table. [#4141](https://github.com/ClickHouse/ClickHouse/pull/4141) ([Artem Zuikov](https://github.com/4ertus2))
- Allow `-C` option of client to work as `-c` option. [#4232](https://github.com/ClickHouse/ClickHouse/pull/4232) ([syominsergey](https://github.com/syominsergey))
- Now option `--password` used without value requires password from stdin. [#4230](https://github.com/ClickHouse/ClickHouse/pull/4230) ([BSD\_Conqueror](https://github.com/bsd-conqueror))
- Added highlighting of unescaped metacharacters in string literals that contain `LIKE` expressions or regexps. [#4327](https://github.com/ClickHouse/ClickHouse/pull/4327) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Added cancelling of HTTP read only queries if client socket goes away. [#4213](https://github.com/ClickHouse/ClickHouse/pull/4213) ([nvartolomei](https://github.com/nvartolomei))
- Now server reports progress to keep client connections alive. [#4215](https://github.com/ClickHouse/ClickHouse/pull/4215) ([Ivan](https://github.com/abyss7))
- Slightly better message with reason for OPTIMIZE query with `optimize_throw_if_noop` setting enabled. [#4294](https://github.com/ClickHouse/ClickHouse/pull/4294) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Added support of `--version` option for clickhouse server. [#4251](https://github.com/ClickHouse/ClickHouse/pull/4251) ([Lopatin Konstantin](https://github.com/k-lopatin))
- Added `--help/-h` option to `clickhouse-server`. [#4233](https://github.com/ClickHouse/ClickHouse/pull/4233) ([Yuriy Baranov](https://github.com/yurriy))
- Added support for scalar subqueries with aggregate function state result. [#4348](https://github.com/ClickHouse/ClickHouse/pull/4348) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
- Improved server shutdown time and ALTERs waiting time. [#4372](https://github.com/ClickHouse/ClickHouse/pull/4372) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Added info about the replicated\_can\_become\_leader setting to system.replicas and add logging if the replica won't try to become leader. [#4379](https://github.com/ClickHouse/ClickHouse/pull/4379) ([Alex Zatelepin](https://github.com/ztlpn))

## ClickHouse Release 19.1[​](#clickhouse-release-19-1 "Direct link to ClickHouse Release 19.1")

### ClickHouse Release 19.1.14, 2019-03-14[​](#clickhouse-release-19-1-14-2019-03-14 "Direct link to ClickHouse Release 19.1.14, 2019-03-14")

- Fixed error `Column ... queried more than once` that may happen if the setting `asterisk_left_columns_only` is set to 1 in case of using `GLOBAL JOIN` with `SELECT *` (rare case). The issue does not exist in 19.3 and newer. [6bac7d8d](https://github.com/ClickHouse/ClickHouse/pull/4692/commits/6bac7d8d11a9b0d6de0b32b53c47eb2f6f8e7062) ([Artem Zuikov](https://github.com/4ertus2))

### ClickHouse Release 19.1.13, 2019-03-12[​](#clickhouse-release-19-1-13-2019-03-12 "Direct link to ClickHouse Release 19.1.13, 2019-03-12")