2023 Changelog

- Add `stderr_reaction` configuration/setting to control the reaction (none, log or throw) when external command stderr has data. This helps make debugging external command easier. [#43210](https://github.com/ClickHouse/ClickHouse/pull/43210) ([Amos Bird](https://github.com/amosbird)).
- Add `partition` column to the `system part_log` and merge table. [#48990](https://github.com/ClickHouse/ClickHouse/pull/48990) ([Jianfei Hu](https://github.com/incfly)).
- The sizes of the (index) uncompressed/mark, mmap and query caches can now be configured dynamically at runtime (without server restart). [#51446](https://github.com/ClickHouse/ClickHouse/pull/51446) ([Robert Schulze](https://github.com/rschu1ze)).
- If a dictionary is created with a complex key, automatically choose the "complex key" layout variant. [#49587](https://github.com/ClickHouse/ClickHouse/pull/49587) ([xiebin](https://github.com/xbthink)).
- Add setting `use_concurrency_control` for better testing of the new concurrency control feature. [#49618](https://github.com/ClickHouse/ClickHouse/pull/49618) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Added suggestions for mistyped names for databases and tables. [#49801](https://github.com/ClickHouse/ClickHouse/pull/49801) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
- While read small files from HDFS by Gluten, we found that it will cost more times when compare to directly query by Spark. And we did something with that. [#50063](https://github.com/ClickHouse/ClickHouse/pull/50063) ([KevinyhZou](https://github.com/KevinyhZou)).
- There were too many worthless error logs after session expiration, which we didn't like. [#50171](https://github.com/ClickHouse/ClickHouse/pull/50171) ([helifu](https://github.com/helifu)).
- Introduce fallback ZooKeeper sessions which are time-bound. Fixed `index` column in system.zookeeper\_connection for DNS addresses. [#50424](https://github.com/ClickHouse/ClickHouse/pull/50424) ([Anton Kozlov](https://github.com/tonickkozlov)).
- Add ability to log when max\_partitions\_per\_insert\_block is reached. [#50948](https://github.com/ClickHouse/ClickHouse/pull/50948) ([Sean Haynes](https://github.com/seandhaynes)).
- Added a bunch of custom commands to clickhouse-keeper-client (mostly to make ClickHouse debugging easier). [#51117](https://github.com/ClickHouse/ClickHouse/pull/51117) ([pufit](https://github.com/pufit)).
- Updated check for connection string in `azureBlobStorage` table function as connection string with "sas" does not always begin with the default endpoint and updated connection URL to include "sas" token after adding Azure's container to URL. [#51141](https://github.com/ClickHouse/ClickHouse/pull/51141) ([SmitaRKulkarni](https://github.com/SmitaRKulkarni)).
- Fix description for filtering sets in the `full_sorting_merge` JOIN algorithm. [#51329](https://github.com/ClickHouse/ClickHouse/pull/51329) ([Tanay Tummalapalli](https://github.com/ttanay)).
- Fixed memory consumption in `Aggregator` when `max_block_size` is huge. [#51566](https://github.com/ClickHouse/ClickHouse/pull/51566) ([Nikita Taranov](https://github.com/nickitat)).
- Add `SYSTEM SYNC FILESYSTEM CACHE` command. It will compare in-memory state of filesystem cache with what it has on disk and fix in-memory state if needed. This is only needed if you are making manual interventions in on-disk data, which is highly discouraged. [#51622](https://github.com/ClickHouse/ClickHouse/pull/51622) ([Kseniia Sumarokova](https://github.com/kssenii)).
- Attempt to create a generic proxy resolver for CH while keeping backwards compatibility with existing S3 storage conf proxy resolver. [#51749](https://github.com/ClickHouse/ClickHouse/pull/51749) ([Arthur Passos](https://github.com/arthurpassos)).
- Support reading tuple subcolumns from file/s3/hdfs/url/azureBlobStorage table functions. [#51806](https://github.com/ClickHouse/ClickHouse/pull/51806) ([Kruglov Pavel](https://github.com/Avogar)).
- Function `arrayIntersect` now returns the values in the order, corresponding to the first argument. Closes [#27622](https://github.com/ClickHouse/ClickHouse/issues/27622). [#51850](https://github.com/ClickHouse/ClickHouse/pull/51850) ([Yarik Briukhovetskyi](https://github.com/yariks5s)).
- Add new queries, which allow to create/drop of access entities in specified access storage or move access entities from one access storage to another. [#51912](https://github.com/ClickHouse/ClickHouse/pull/51912) ([pufit](https://github.com/pufit)).
- Make `ALTER TABLE FREEZE` queries not replicated in the Replicated database engine. [#52064](https://github.com/ClickHouse/ClickHouse/pull/52064) ([Mike Kot](https://github.com/myrrc)).
- Added possibility to flush system tables on unexpected shutdown. [#52174](https://github.com/ClickHouse/ClickHouse/pull/52174) ([Alexey Gerasimchuck](https://github.com/Demilivor)).
- Fix the case when `s3` table function refused to work with pre-signed URLs. close [#50846](https://github.com/ClickHouse/ClickHouse/issues/50846). [#52310](https://github.com/ClickHouse/ClickHouse/pull/52310) ([chen](https://github.com/xiedeyantu)).
- Add column `name` as an alias to `event` and `metric` in the `system.events` and `system.metrics` tables. Closes [#51257](https://github.com/ClickHouse/ClickHouse/issues/51257). [#52315](https://github.com/ClickHouse/ClickHouse/pull/52315) ([chen](https://github.com/xiedeyantu)).
- Added support of syntax `CREATE UNIQUE INDEX` in parser as a no-op for better SQL compatibility. `UNIQUE` index is not supported. Set `create_index_ignore_unique = 1` to ignore UNIQUE keyword in queries. [#52320](https://github.com/ClickHouse/ClickHouse/pull/52320) ([Ilya Yatsishin](https://github.com/qoega)).
- Add support of predefined macro (`{database}` and `{table}`) in some Kafka engine settings: topic, consumer, client\_id, etc. [#52386](https://github.com/ClickHouse/ClickHouse/pull/52386) ([Yury Bogomolov](https://github.com/ybogo)).
- Disable updating the filesystem cache during backup/restore. Filesystem cache must not be updated during backup/restore, it seems it just slows down the process without any profit (because the BACKUP command can read a lot of data and it's no use to put all the data to the filesystem cache and immediately evict it). [#52402](https://github.com/ClickHouse/ClickHouse/pull/52402) ([Vitaly Baranov](https://github.com/vitlibar)).
- The configuration of S3 endpoint allow using it from the root, and append '/' automatically if needed. [#47809](https://github.com/ClickHouse/ClickHouse/issues/47809). [#52600](https://github.com/ClickHouse/ClickHouse/pull/52600) ([xiaolei565](https://github.com/xiaolei565)).
- For clickhouse-local allow positional options and populate global UDF settings (user\_scripts\_path and user\_defined\_executable\_functions\_config). [#52643](https://github.com/ClickHouse/ClickHouse/pull/52643) ([Yakov Olkhovskiy](https://github.com/yakov-olkhovskiy)).
- `system.asynchronous_metrics` now includes metrics "QueryCacheEntries" and "QueryCacheBytes" to inspect the query cache. [#52650](https://github.com/ClickHouse/ClickHouse/pull/52650) ([Robert Schulze](https://github.com/rschu1ze)).
- Added possibility to use `s3_storage_class` parameter in the `SETTINGS` clause of the `BACKUP` statement for backups to S3. [#52658](https://github.com/ClickHouse/ClickHouse/pull/52658) ([Roman Vasin](https://github.com/rvasin)).
- Add utility `print-backup-info.py` which parses a backup metadata file and prints information about the backup. [#52690](https://github.com/ClickHouse/ClickHouse/pull/52690) ([Vitaly Baranov](https://github.com/vitlibar)).