2020 Changelog

- Adding support for PREWHERE in live view tables. [#11495](https://github.com/ClickHouse/ClickHouse/pull/11495) ([vzakaznikov](https://github.com/vzakaznikov)).
- Automatically update DNS cache, which is used to check if user is allowed to connect from an address. [#11487](https://github.com/ClickHouse/ClickHouse/pull/11487) ([tavplubix](https://github.com/tavplubix)).
- OPTIMIZE FINAL will force merge even if concurrent merges are performed. This closes [#11309](https://github.com/ClickHouse/ClickHouse/issues/11309) and closes [#11322](https://github.com/ClickHouse/ClickHouse/issues/11322). [#11346](https://github.com/ClickHouse/ClickHouse/pull/11346) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Suppress output of cancelled queries in clickhouse-client. In previous versions result may continue to print in terminal even after you press Ctrl+C to cancel query. This closes [#9473](https://github.com/ClickHouse/ClickHouse/issues/9473). [#11342](https://github.com/ClickHouse/ClickHouse/pull/11342) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Now history file is updated after each query and there is no race condition if multiple clients use one history file. This fixes [#9897](https://github.com/ClickHouse/ClickHouse/issues/9897). [#11453](https://github.com/ClickHouse/ClickHouse/pull/11453) ([Tagir Kuskarov](https://github.com/kuskarov)).
- Better log messages in while reloading configuration. [#11341](https://github.com/ClickHouse/ClickHouse/pull/11341) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Remove trailing whitespaces from formatted queries in `clickhouse-client` or `clickhouse-format` in some cases. [#11325](https://github.com/ClickHouse/ClickHouse/pull/11325) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Add setting "output\_format\_pretty\_max\_value\_width". If value is longer, it will be cut to avoid output of too large values in terminal. This closes [#11140](https://github.com/ClickHouse/ClickHouse/issues/11140). [#11324](https://github.com/ClickHouse/ClickHouse/pull/11324) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Better exception message in case when there is shortage of memory mappings. This closes [#11027](https://github.com/ClickHouse/ClickHouse/issues/11027). [#11316](https://github.com/ClickHouse/ClickHouse/pull/11316) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Support (U)Int8, (U)Int16, Date in ASOF JOIN. [#11301](https://github.com/ClickHouse/ClickHouse/pull/11301) ([Artem Zuikov](https://github.com/4ertus2)).
- Support kafka\_client\_id parameter for Kafka tables. It also changes the default `client.id` used by ClickHouse when communicating with Kafka to be more verbose and usable. [#11252](https://github.com/ClickHouse/ClickHouse/pull/11252) ([filimonov](https://github.com/filimonov)).
- Keep the value of `DistributedFilesToInsert` metric on exceptions. In previous versions, the value was set when we are going to send some files, but it is zero, if there was an exception and some files are still pending. Now it corresponds to the number of pending files in filesystem. [#11220](https://github.com/ClickHouse/ClickHouse/pull/11220) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Add support for multi-word data type names (such as `DOUBLE PRECISION` and `CHAR VARYING`) for better SQL compatibility. [#11214](https://github.com/ClickHouse/ClickHouse/pull/11214) ([Павел Потемкин](https://github.com/Potya)).
- Provide synonyms for some data types. [#10856](https://github.com/ClickHouse/ClickHouse/pull/10856) ([Павел Потемкин](https://github.com/Potya)).
- The query log is now enabled by default. [#11184](https://github.com/ClickHouse/ClickHouse/pull/11184) ([Ivan Blinkov](https://github.com/blinkov)).
- Show authentication type in table system.users and while executing SHOW CREATE USER query. [#11080](https://github.com/ClickHouse/ClickHouse/pull/11080) ([Vitaly Baranov](https://github.com/vitlibar)).
- Remove data on explicit `DROP DATABASE` for `Memory` database engine. Fixes [#10557](https://github.com/ClickHouse/ClickHouse/issues/10557). [#11021](https://github.com/ClickHouse/ClickHouse/pull/11021) ([tavplubix](https://github.com/tavplubix)).
- Set thread names for internal threads of rdkafka library. Make logs from rdkafka available in server logs. [#10983](https://github.com/ClickHouse/ClickHouse/pull/10983) ([Azat Khuzhin](https://github.com/azat)).
- Support for unicode whitespaces in queries. This helps when queries are copy-pasted from Word or from web page. This fixes [#10896](https://github.com/ClickHouse/ClickHouse/issues/10896). [#10903](https://github.com/ClickHouse/ClickHouse/pull/10903) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Allow large UInt types as the index in function `tupleElement`. [#10874](https://github.com/ClickHouse/ClickHouse/pull/10874) ([hcz](https://github.com/hczhcz)).
- Respect prefer\_localhost\_replica/load\_balancing on INSERT into Distributed. [#10867](https://github.com/ClickHouse/ClickHouse/pull/10867) ([Azat Khuzhin](https://github.com/azat)).
- Introduce `min_insert_block_size_rows_for_materialized_views`, `min_insert_block_size_bytes_for_materialized_views` settings. This settings are similar to `min_insert_block_size_rows` and `min_insert_block_size_bytes`, but applied only for blocks inserted into `MATERIALIZED VIEW`. It helps to control blocks squashing while pushing to MVs and avoid excessive memory usage. [#10858](https://github.com/ClickHouse/ClickHouse/pull/10858) ([Azat Khuzhin](https://github.com/azat)).
- Get rid of exception from replicated queue during server shutdown. Fixes [#10819](https://github.com/ClickHouse/ClickHouse/issues/10819). [#10841](https://github.com/ClickHouse/ClickHouse/pull/10841) ([alesapin](https://github.com/alesapin)).
- Ensure that `varSamp`, `varPop` cannot return negative results due to numerical errors and that `stddevSamp`, `stddevPop` cannot be calculated from negative variance. This fixes [#10532](https://github.com/ClickHouse/ClickHouse/issues/10532). [#10829](https://github.com/ClickHouse/ClickHouse/pull/10829) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Better DNS exception message. This fixes [#10813](https://github.com/ClickHouse/ClickHouse/issues/10813). [#10828](https://github.com/ClickHouse/ClickHouse/pull/10828) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Change HTTP response code in case of some parse errors to 400 Bad Request. This fix [#10636](https://github.com/ClickHouse/ClickHouse/issues/10636). [#10640](https://github.com/ClickHouse/ClickHouse/pull/10640) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Print a message if clickhouse-client is newer than clickhouse-server. [#10627](https://github.com/ClickHouse/ClickHouse/pull/10627) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Adding support for `INSERT INTO [db.]table WATCH` query. [#10498](https://github.com/ClickHouse/ClickHouse/pull/10498) ([vzakaznikov](https://github.com/vzakaznikov)).
- Allow to pass quota\_key in clickhouse-client. This closes [#10227](https://github.com/ClickHouse/ClickHouse/issues/10227). [#10270](https://github.com/ClickHouse/ClickHouse/pull/10270) ([alexey-milovidov](https://github.com/alexey-milovidov)).