2021 Changelog

#### Build/Testing/Packaging Improvement[​](#buildtestingpackaging-improvement-1 "Direct link to Build/Testing/Packaging Improvement")

- Add support for FreeBSD builds for Aarch64 machines. [#29952](https://github.com/ClickHouse/ClickHouse/pull/29952) ([MikaelUrankar](https://github.com/MikaelUrankar)).
- Recursive submodules are no longer needed for ClickHouse. [#30315](https://github.com/ClickHouse/ClickHouse/pull/30315) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- ClickHouse can be statically built with Musl. This is added as experiment, it does not support building `odbc-bridge`, `library-bridge`, integration with CatBoost and some libraries. [#30248](https://github.com/ClickHouse/ClickHouse/pull/30248) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Enable `Protobuf`, `Arrow`, `ORC`, `Parquet` for `AArch64` and `Darwin` (macOS) builds. This closes [#29248](https://github.com/ClickHouse/ClickHouse/issues/29248). This closes [#28018](https://github.com/ClickHouse/ClickHouse/issues/28018). [#30015](https://github.com/ClickHouse/ClickHouse/pull/30015) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Add cross-build for PowerPC (powerpc64le). This closes [#9589](https://github.com/ClickHouse/ClickHouse/issues/9589). Enable support for interaction with MySQL for AArch64 and PowerPC. This closes [#26301](https://github.com/ClickHouse/ClickHouse/issues/26301). [#30010](https://github.com/ClickHouse/ClickHouse/pull/30010) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Leave only required files in cross-compile toolchains. Include them as submodules (earlier they were downloaded as tarballs). [#29974](https://github.com/ClickHouse/ClickHouse/pull/29974) ([alexey-milovidov](https://github.com/alexey-milovidov)).
- Implemented structure-aware fuzzing approach in ClickHouse for select statement parser. [#30012](https://github.com/ClickHouse/ClickHouse/pull/30012) ([Paul](https://github.com/PaulCher)).
- Turning on experimental constexpr expressions evaluator for clang to speed up template code compilation. [#29668](https://github.com/ClickHouse/ClickHouse/pull/29668) ([myrrc](https://github.com/myrrc)).
- Add ability to compile using newer version fo glibc without using new symbols. [#29594](https://github.com/ClickHouse/ClickHouse/pull/29594) ([Azat Khuzhin](https://github.com/azat)).
- Reduce Debug build binary size by clang optimization option. [#28736](https://github.com/ClickHouse/ClickHouse/pull/28736) ([flynn](https://github.com/ucasfl)).
- Now all images for CI will be placed in the separate dockerhub repo. [#28656](https://github.com/ClickHouse/ClickHouse/pull/28656) ([alesapin](https://github.com/alesapin)).
- Improve support for build with clang-13. [#28046](https://github.com/ClickHouse/ClickHouse/pull/28046) ([Sergei Semin](https://github.com/syominsergey)).
- Add ability to print raw profile events to `clickhouse-client` (This can be useful for debugging and for testing). [#30064](https://github.com/ClickHouse/ClickHouse/pull/30064) ([Azat Khuzhin](https://github.com/azat)).
- Add time dependency for clickhouse-server unit (systemd and sysvinit init). [#28891](https://github.com/ClickHouse/ClickHouse/pull/28891) ([Azat Khuzhin](https://github.com/azat)).
- Reload stacktrace cache when symbol is reloaded. [#28137](https://github.com/ClickHouse/ClickHouse/pull/28137) ([Amos Bird](https://github.com/amosbird)).

#### Bug Fix[​](#bug-fix "Direct link to Bug Fix")