2020 Changelog

- Improved logging when working with `S3` table engine. [#8251](https://github.com/ClickHouse/ClickHouse/pull/8251) ([Grigory Pervakov](https://github.com/GrigoryPervakov))
- Printed help message when no arguments are passed when calling `clickhouse-local`. This fixes [#5335](https://github.com/ClickHouse/ClickHouse/issues/5335). [#8230](https://github.com/ClickHouse/ClickHouse/pull/8230) ([Andrey Nagorny](https://github.com/Melancholic))
- Add setting `mutations_sync` which allows to wait `ALTER UPDATE/DELETE` queries synchronously. [#8237](https://github.com/ClickHouse/ClickHouse/pull/8237) ([alesapin](https://github.com/alesapin))
- Allow to set up relative `user_files_path` in `config.xml` (in the way similar to `format_schema_path`). [#7632](https://github.com/ClickHouse/ClickHouse/pull/7632) ([hcz](https://github.com/hczhcz))
- Add exception for illegal types for conversion functions with `-OrZero` postfix. [#7880](https://github.com/ClickHouse/ClickHouse/pull/7880) ([Andrey Konyaev](https://github.com/akonyaev90))
- Simplify format of the header of data sending to a shard in a distributed query. [#8044](https://github.com/ClickHouse/ClickHouse/pull/8044) ([Vitaly Baranov](https://github.com/vitlibar))
- `Live View` table engine refactoring. [#8519](https://github.com/ClickHouse/ClickHouse/pull/8519) ([vzakaznikov](https://github.com/vzakaznikov))
- Add additional checks for external dictionaries created from DDL-queries. [#8127](https://github.com/ClickHouse/ClickHouse/pull/8127) ([alesapin](https://github.com/alesapin))
- Fix error `Column ... already exists` while using `FINAL` and `SAMPLE` together, e.g. `select count() from table final sample 1/2`. Fixes [#5186](https://github.com/ClickHouse/ClickHouse/issues/5186). [#7907](https://github.com/ClickHouse/ClickHouse/pull/7907) ([Nikolai Kochetov](https://github.com/KochetovNicolai))
- Now table the first argument of `joinGet` function can be table identifier. [#7707](https://github.com/ClickHouse/ClickHouse/pull/7707) ([Amos Bird](https://github.com/amosbird))
- Allow using `MaterializedView` with subqueries above `Kafka` tables. [#8197](https://github.com/ClickHouse/ClickHouse/pull/8197) ([filimonov](https://github.com/filimonov))
- Now background moves between disks run it the seprate thread pool. [#7670](https://github.com/ClickHouse/ClickHouse/pull/7670) ([Vladimir Chebotarev](https://github.com/excitoon))
- `SYSTEM RELOAD DICTIONARY` now executes synchronously. [#8240](https://github.com/ClickHouse/ClickHouse/pull/8240) ([Vitaly Baranov](https://github.com/vitlibar))
- Stack traces now display physical addresses (offsets in object file) instead of virtual memory addresses (where the object file was loaded). That allows the use of `addr2line` when binary is position independent and ASLR is active. This fixes [#8360](https://github.com/ClickHouse/ClickHouse/issues/8360). [#8387](https://github.com/ClickHouse/ClickHouse/pull/8387) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Support new syntax for row-level security filters: `<table name='table_name'>...</table>`. Fixes [#5779](https://github.com/ClickHouse/ClickHouse/issues/5779). [#8381](https://github.com/ClickHouse/ClickHouse/pull/8381) ([Ivan](https://github.com/abyss7))
- Now `cityHash` function can work with `Decimal` and `UUID` types. Fixes [#5184](https://github.com/ClickHouse/ClickHouse/issues/5184). [#7693](https://github.com/ClickHouse/ClickHouse/pull/7693) ([Mikhail Korotov](https://github.com/millb))
- Removed fixed index granularity (it was 1024) from system logs because it's obsolete after implementation of adaptive granularity. [#7698](https://github.com/ClickHouse/ClickHouse/pull/7698) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Enabled MySQL compatibility server when ClickHouse is compiled without SSL. [#7852](https://github.com/ClickHouse/ClickHouse/pull/7852) ([Yuriy Baranov](https://github.com/yurriy))
- Now server checksums distributed batches, which gives more verbose errors in case of corrupted data in batch. [#7914](https://github.com/ClickHouse/ClickHouse/pull/7914) ([Azat Khuzhin](https://github.com/azat))
- Support `DROP DATABASE`, `DETACH TABLE`, `DROP TABLE` and `ATTACH TABLE` for `MySQL` database engine. [#8202](https://github.com/ClickHouse/ClickHouse/pull/8202) ([Winter Zhang](https://github.com/zhang2014))
- Add authentication in S3 table function and table engine. [#7623](https://github.com/ClickHouse/ClickHouse/pull/7623) ([Vladimir Chebotarev](https://github.com/excitoon))
- Added check for extra parts of `MergeTree` at different disks, in order to not allow to miss data parts at undefined disks. [#8118](https://github.com/ClickHouse/ClickHouse/pull/8118) ([Vladimir Chebotarev](https://github.com/excitoon))
- Enable SSL support for Mac client and server. [#8297](https://github.com/ClickHouse/ClickHouse/pull/8297) ([Ivan](https://github.com/abyss7))
- Now ClickHouse can work as MySQL federated server (see <https://dev.mysql.com/doc/refman/5.7/en/federated-create-server.html>). [#7717](https://github.com/ClickHouse/ClickHouse/pull/7717) ([Maxim Fedotov](https://github.com/MaxFedotov))
- `clickhouse-client` now only enable `bracketed-paste` when multiquery is on and multiline is off. This fixes [#7757](https://github.com/ClickHouse/ClickHouse/issues/7757). [#7761](https://github.com/ClickHouse/ClickHouse/pull/7761) ([Amos Bird](https://github.com/amosbird))
- Support `Array(Decimal)` in `if` function. [#7721](https://github.com/ClickHouse/ClickHouse/pull/7721) ([Artem Zuikov](https://github.com/4ertus2))
- Support Decimals in `arrayDifference`, `arrayCumSum` and `arrayCumSumNegative` functions. [#7724](https://github.com/ClickHouse/ClickHouse/pull/7724) ([Artem Zuikov](https://github.com/4ertus2))
- Added `lifetime` column to `system.dictionaries` table. [#6820](https://github.com/ClickHouse/ClickHouse/issues/6820) [#7727](https://github.com/ClickHouse/ClickHouse/pull/7727) ([kekekekule](https://github.com/kekekekule))
- Improved check for existing parts on different disks for `*MergeTree` table engines. Addresses [#7660](https://github.com/ClickHouse/ClickHouse/issues/7660). [#8440](https://github.com/ClickHouse/ClickHouse/pull/8440) ([Vladimir Chebotarev](https://github.com/excitoon))
- Integration with `AWS SDK` for `S3` interactions which allows to use all S3 features out of the box. [#8011](https://github.com/ClickHouse/ClickHouse/pull/8011) ([Pavel Kovalenko](https://github.com/Jokser))
- Added support for subqueries in `Live View` tables. [#7792](https://github.com/ClickHouse/ClickHouse/pull/7792) ([vzakaznikov](https://github.com/vzakaznikov))
- Check for using `Date` or `DateTime` column from `TTL` expressions was removed. [#7920](https://github.com/ClickHouse/ClickHouse/pull/7920) ([Vladimir Chebotarev](https://github.com/excitoon))
- Information about disk was added to `system.detached_parts` table. [#7833](https://github.com/ClickHouse/ClickHouse/pull/7833) ([Vladimir Chebotarev](https://github.com/excitoon))
- Now settings `max_(table|partition)_size_to_drop` can be changed without a restart. [#7779](https://github.com/ClickHouse/ClickHouse/pull/7779) ([Grigory Pervakov](https://github.com/GrigoryPervakov))
- Slightly better usability of error messages. Ask user not to remove the lines below `Stack trace:`. [#7897](https://github.com/ClickHouse/ClickHouse/pull/7897) ([alexey-milovidov](https://github.com/alexey-milovidov))
- Better reading messages from `Kafka` engine in various formats after [#7935](https://github.com/ClickHouse/ClickHouse/issues/7935). [#8035](https://github.com/ClickHouse/ClickHouse/pull/8035) ([Ivan](https://github.com/abyss7))
- Better compatibility with MySQL clients which don't support `sha2_password` auth plugin. [#8036](https://github.com/ClickHouse/ClickHouse/pull/8036) ([Yuriy Baranov](https://github.com/yurriy))
- Support more column types in MySQL compatibility server. [#7975](https://github.com/ClickHouse/ClickHouse/pull/7975) ([Yuriy Baranov](https://github.com/yurriy))